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  1. Hi there, new to the forum. Looking for information if someone already deal with this problems. 2014 Silverado 5.3 I changed spark plugs, cables, all the injectors. And after that the truck worked well for 2 days after that I started getting code for misfire cilynder 4, the stabilitrack light, engine power reduce, I know I need to remove the valve cover and check for lifters, but I just want to know if someone already deal with this and what was the fix for this. I like the truck but it just sucks to many issues with this engines. Thanks.
  2. 2007 Silverado 5.3 V8 with AFM with 180,000 miles Truck had lifter ticking sound and white smoke upon every start up which would go away after a few minutes, no check engine light Replacement list : - headgasket - valve gaskets - upgraded drivers side valve cover - valve stem seals - intake manifold gasket - exhaust manifold gasket - 8 new afm lifters - 8 new non-afm lifters - head gasket bolts - engine coolant temperature sensor - spark plugs - spark plug wires - fuel injectors - water pump - thermostat - cam sensor - crank sensor After completion of engine reassembly no longer had white smoke upon start up and no ticking sound but flashing check engine light code p0300. Code p0300 was for cylinder #1, #4, & #7 Moved coil packs between cylinder #1 and #2 to see if coil packs was bad but no change. Set engine at TDC before installing the rocker arms. All bolts have been properly torque and no parts have been left unplugged or uninstall. Any possible advice would be helpful
  3. I'm having a bit of a dilemma here. I have a 98 Yukon and back in January it started missing. I replaced the plugs, wires, cap, and rotor, and it worked fine for a while. A few weeks ago, it started missing again, this time much worse. I replaced the O2 sensors and that didn't fix it, so I took it to the dealership to have it diagnosed. The dealership said that the distributor and the injectors were bad. I replaced the distributor with one from a salvage yard, and upgraded the old spider to a brand new AC Delco MFI injector system. I just finished replacing the injectors yesterday morning. I cleared the codes and took it for a drive. It all seemed fine, but then I noticed a slight hesitation and sure enough it showed the same misfire code. At this point I feel like I've done everything I can. When I put the intake back together I noticed a few things. One is that one of the screw holes on the new distributor is stripped, and wouldn't tighten down all the way, so I'm wondering if a slightly loose cap could be having an effect, and I'm also wondering if the plugs could have gotten messed up while the engine was missing really badly and if I should replace them again. I didn't replace the MAF senor when I did the O2 sensors, and I'm wondering if I should have, and I'm also wondering if I should take out the salvaged distributor and replace it with a new one. I found a good deal on one through Amazon. Knowing all that, is there anything else that could be causing this slight hesitation after all the work I've already done? Thanks in advance, Eric
  4. I've got a 2014 GMC Sierra L83 single cab... I recently decided its time I start getting some performance out of my truck. I installed: L86 Thottle body and intake manifold 1 7/8 header + full 3 inch exhaust (magnaflow muffler) Stage 2 GPI cam kit + DOD Delete Transmission Oil cooler I had the car dyno tuned and everything went perfect. We later had a few trial runs on the street and hit issues with sort of a misfire at specific rpms and gears... 2nd gear at 4,200ish rpm it would have a slight nudge and again at 5,200ish another drop and kick. It would happen almost all the time. We thought it would be the spark plug cables, went and got MSD plug cables added those, tried again, same thing! Spark plugs are new, fuel injectors are serviced with zero issues... the car ran perfectly before we did all of this... The tuner now tried raising the oil pressure in the transmission thinking its a gear slippage due to the oil pressure. Tried again, same thing!! We've ruled out alot of the problems, now theyre saying that its the disc thats slipping in the transmission which would make sense but I want to get ideas as I'm spending money trying to fix the issues that we're not a 100% sure about. Can you guys let me know if anyone went through anything remotely similar or if you have any views on the matter. Many thanks!!!!
  5. I had a rough idle ans I noticed my tahoe losing power ans engine started missing. Code acanner said random misfire. Changed plugs, wires, and crankshaft sensor. It started ran finw for about 30 seconds- 1 minute maybe, then it just died instantly. Hasnt started since.
  6. I just put a new 6.0 long block in my 2002 chevy Silverado and it won't start. All new sensors, plugs and wires. When I go to start it it back fires through the intake. Plugs are soaked in fuel as well. I've checked to make sure nothing is unplugged....any suggestions?
  7. I recently bought a used 2016 Sierra Denali 5.3L 4x4 in March with 48k miles. Truck has been great until yesterday (now 52k miles) when I ease into the gas it shudders and shakes like crazy until i punch it. The tach is bouncing up and down and it doesn't matter if it's in v8 or v4. It almost feels like it's a misfire but it's weird that it only does it when I'm easing into the throttle or going uphill. The truck has the 8 speed transmission. Has anyone else ran into something like this and would the manufacturer warranty cover the fix for this?
  8. Looking for help/instructions on replacing fuel injector/s for a 2017 5.3L Silverado. Truck has 80K miles on it and a #5 misfire. Dealer ran a diagnostics and said the injector needs to be replaced. I found a couple pictures on the forum of the fuel injectors but very little information on steps to replace them. The only videos I could find online were for older models with a different injector diagram. Talking to the dealer they quoted me $770 to replace a single injector, gaskets and piping associated with the job. 4 hours or labor and $240 in parts. Are there any good instructions or videos out there on replacing fuel injectors on a 2017 Silverado? I've never done a job like this but consider myself mechanically include, is this an easy enough job or should I leave this to the dealer to do? I know they say if your replacing a single injector you might as well replace all 4 on one bank but is that really necessary, $110 a piece and if the other 3 are fine why replace them? The dealer said the piping and gaskets must be replaced even for a single injector replacement job. Is this all necessary? I've never had another vehicle with injector problems so this will be a first. Parts quoted- 12687650 (1) injector 12626354 (8) gaskets 12677002 (1) pipe 12677004 (1) pipe Any help, links to instruction/diagrams or videos would be awesome! I enjoy working on these projects rather than paying someone else to do the work since you learn something every time. I also want it done right. Thanks all in advance!
  9. Currently in the process of trouble shooting a p0304 code. Ruled out a bad coil pack by hooking an ohm meter to it and also swapping cylinder 2 & 4 to see if the the Mis fire would follow. Replaced spark plugs, plug wires, and put a can of sea-foam in the intake. Not hearing any abnormal sounds coming from the engine while running. Just a steady misfire on 4. I’m thinking it is a bad injector. Anyone else experience something similar, and to also see if anyone yet has tackled changing the injectors on the new models. Thank you
  10. I did a search here for it but came up empty. Last week, my Check Engine Light came on briefly while on the highway. Just before and after that I noticed a reduced lack of response to giving it more throttle. I had a local guy pull the CEL code and said it came up as #7 Cylinder Misfire. I'm at 55,000 miles and am off warranty. The truck is a '14 with a 5.3. Any suggestions, or thoughts how serious this may be ?
  11. (I posted this on another board, if you've seen it there and replied then disregard. ) Hey folks, I’m new here. I’ve been reading post for a while, my vehicle before the 2010 Tahoe I now have was an ’03 Tahoe. I’m looking for input on a problem I can’t wrap my mind around. A quick bit of info about me, I’m one of those older guys from the days of points and condensers and manually setting your timing (1970’s era) etc. I never built ‘hot rods’ so I never got deep into the technical side of things, but I have rebuilt 3 or 4 engines over the years and usually do all my own repairs. I’m not into engine modifications, pretty much an OEM spec kind of guy. I do commercial low voltage electronic systems for a living, so I have no problem with automotive electrical, and have a decent understanding of module control of inputs and outputs. I’m not a pro at this by any means, but I’m also not a newbe. No doubt you can get over my head if you happen to be a pro and have some input, but hopefully you won’t have to candy coat it too much. So back in November, I traded my ’03 Tahoe in for a 2010 LT Z71 Tahoe with a 5.3 and 120,000 miles. I plugged in my cheap code reader and there were no codes and all the monitors were ready, and it ran fine, so, no need to fix what’s not broken. I wasn’t real pleased with the mileage, it averaged a little better than 13.5 mpg, but figured I’d work on that as time went on. I did put new plugs and plug wires in the first month. Back in April it started idling rough, but didn’t throw any codes. Knowing it’s 8 years old with over 120,000 miles, and not knowing the history, I don’t have a problem replacing parts so I’ll know what I have, especially anything that will help gas mileage. I replaced the throttle body and position sensor (along with the accelerator pedal w/position senor), and once the idle speed settled down it was still rough, and threw a P0305 code (cylinder 5 misfire). I’ve been fighting that code ever since. I have a scan tool, I can see the misfire counter add up on cylinder 5, and it seems to be only at an idle. I moved plugs, plug wires, coils and injectors to other cylinders, but the misfire at idle stays on cylinder 5. I researched the hell out of Active Fuel Management, which I have, and I know all the lifter issues and problems they can have, but AFM is on cylinders 1, 4, 6 and 7, and my misfire is on cylinder 5. It’s not consuming oil like the ones with the AFM lifter problem. I’ve replaced the Mass Air Flow sensor, MAP sensor, water temp sensor was replaced when I changed the water pump back in February (shaft bearing was starting to squalk), I changed the oil pressure sensor (and the VLOM screen underneath it) just to be sure the oil pressure reading I was seeing was accurate. I changed the vapor canister purge valve and vapor canister vent valve (problem with gas pump handle disengaging while filling the tank), I changed both the crank and cam position sensors (and did the crank position relearn), still have the misfire. I’ve checked compression with all the plugs out, over 180 pounds on every cylinder, including cylinder 5. I checked vacuum (inserting a ‘T’ at the brake booster vacuum connection) 19 inches at idle, goes to 17 inches if the AC is on. I have a noticeable loss in power, most of the time it feels like I’m towing a pontoon boat. My gas milage is down around 12 mpg or less. I noticed on my scan tool the long term fuel trim on bank 2 was running about +12 at idle, but would go down to about +1 while driving, while not the same bank as cylinder, assumed I had a vacuum leak on bank 2. I also noticed O2 sensor Bank 1 Sensor 2 constantly stayed around 810 mV regardless of what the others were doing. Thinking the O2 sensors may be the original ones I went ahead and changed them. I suspected that if they were getting old and slow and sending bad info to the ECM, that when it was open loop (with a vacuum leak) and then going closed loop and seeing bogus info from the O2 sensors and making fuel adjustments for that that it was constantly changing fuel mixture as it bounced in and out of open and closed loop mode, which I thought may be why it was so sluggish. I decided to change the intake gaskets, went with Felpro. While I had the intake off I went ahead and changed the fuel injectors. The long term fuel trim is back down low again so apparently I did have some vacuum leaks. And now I feel better about the fuel injectors actually delivering what the ECM thinks they are delivering. But, still have the misfire on cylinder 5 and recurring P0305 within two drive cycles. I can pull the injector electrical connector off cylinder 5 while idling and it really doesn’t change the idle speed. At that point I was suspecting maybe the ECM is stuttering on the pulses to the cylinder 5 injector. I put a noid light on the injector connector for cylinder 5 and at an idle (when the scan tool is steadily counting misfires on cylinder 5) I’m seeing a nice steady light pulse not missing a beat. I put a spark indicator on the spark plug, same thing, steady light pulse, not missing a beat. Now, off with the valve cover. Cranking the engine over I can see both valves on cylinder 5 open and close as they should. I put #5 at TDC and removed the rocker arms, no visible damage, no cracks, no wear. Pulled the push rods, not plugged, you can clearly see light thru them and their walls just like looking through a new straw. Both valve springs look fine, neither is broken, both seem to be keeping the valve closed tightly. That didn’t satisfy me, so (after reinstalling the rockers) I hung the coil pack with some string, reconnected the harness and plugs and started the motor to watch the rockers in action. Neither valve missed a beat, both opening and closing the same amount as the other valves by just watching them (I’m sure there’s probably a scientific way to measure that, but with the naked eye they appear to be working just fine) Both pushrods are pushing out oil on top of the rock arm, not tapping any louder than the other, so I’m thinking the lifters are. I got my stethoscope and listened to the fastening nut on all 8 rocker arms. I will say this. On seven of the eight rocker arms you can hear that whirring sound of the engine and a slight tapping sound as the valve operates, but the exhaust valve of cylinder 5 was a little louder and sounded kind of rattley in between taps. Not extremely louder than the others with the stethoscope, but enough to notice it was not as smooth and quite as the others. BUT, still opening and closing the valve and pumping oil. And with the naked ear, it’s no louder than any of the others. I found a TSB (#11-06-04-007B) about changing the throttle position sensor that said for Tahoes from ’08-’10 if you put a new throttle position sensor that you MUST reflash the ECM with he latest software, but from ’11 up the reflash was not required. Mine is a 10 and I have changed the throttle body/throttle position sensor as and assembly, so I put the old one back on for now just to be sure that’s not causing an issue. So I’m at a loss. I’ve used all ACDelco parts (except for the Felpro intake gaskets) I’ve eliminated every external thing I can think of that could cause a misfire, I have compression, vacuum, fuel pressure running 58-60 psi key on and engine off, and stays around 58 psi at idle, no vacuum leaks. The one and only thing I’ve found wrong with cylinder 5 is a little extra noise on the exhaust rocker are when listening with a stethoscope. I may be wrong, but I can’t believe THAT is enough to cause a constant misfire since the valve is opening and closing as expected. The only thing I haven’t changed is the knock sensors. Starting in ’07, they moved them from underneath the intake to down on each side of the of the lower block. Easy to get to now, and ironically the one on the left side is about where the #5 cylinder is. The scan tool shows no knock on any cylinder. I really don’t thing a bad knock sensor would cause a cylinder specific misfire, but they are less than $8 each at Rockauto, so I ordered a couple of them. On a side note, I’ve also ran some Seafoam in the oil for about 200 miles thinking if the problem was a lifter it would loosen up. I haven’t tried Marvel Mystery Oil yet. If you have any input that would help I would appreciate it. I’ve seen posts about misfires on discussion boards, but most of the time there is no follow up post if they fixed the problem. If I find a solution I will absolutely post what I did to resolve it. Thanks for reading if you got this far, sorry it’s so long.
  12. So i have a misfire...i change my cap, rotor, plugs, ignition coil, ignition control module, i even replaced my lower intake manifold gasket and timed my distributor. Then after all that i still had a misfire. What more could it be...a timing chain!?
  13. I need some help I’m not a mechanic totally but I have been going to school for it and my 03 Silverado 5.3 is misfiring and I don’t know what the problem could be I replaced the spark plugs coils and all the cylinders are getting spark and I had a compression test and the the cylinders have near perfect compression so I don’t think it’d be that. I even replaced the ecu/pcm in it and nothing changed it’s a hard idle and had no power can’t even make it a block really it also dies when I hit the brakes after going anywhere over 5 mph.
  14. Fixed! See page 2 update. Rebuilt Trans! 2014 Sierra 1500 5.3 120k miles Hey all, I searched and read some of the transmission threads but it wasn't helpful so hoping someone can guide me or had the same issue.. Truck has been running great no issues, one morning i go to work as usual and half way into the commute i get this skipping/shudder when under load. I let off it goes away. RPM is steady at idle and its not doing it or is not noticeable in cruise. No codes. Does it in Manual, all gears and all speeds. Only when i get on the gas. Power is less, it feels like a slipping trans but also feels like a misfire. Plugs are assumed to be originals so tonight im replacing all to see if it fixes it, if not: they needed to be done anyways so no harm done. Trans has been flushed at 95k at GM dealer. My next option is another flush. Any ideas?
  15. I have a 1993 GMC Sierra C1500 v6 4.3L with an automatic transmission and i have tried replacing the distributor cap, router button, spark-plugs and the module that sits under the distributor cap but nothing works it just rolls tries to kick and if it does start it dies instantly. also when trying to start it smoke rolls out of the throttle body I have no clue how to fix this
  16. Hey guys, first post on here and I've got something that stumped me 100%. I have a 2005 silverado 1500 flex vin code Z. It Idles rough it has terrible acceleration, wide open throttle it takes off like nothing is wrong. It misses on 7 every time, misses on 2 every other time, every other cylinder misses here and there. No misses when in park and rpms are kept about 2500. CEL flashes most the time when accelerating (except WOT) otherwise the light is on solid. It has 220k on it and I have replaced alot of parts. New parts All 4 02 sensors OEM Plugs OEM wires OEM Fuel pump OEM Throttle body cleaned 3 stage fuel system cleaner BG Brand Air filter believe it or not OEM again New transfer case (unrelated issue) I have covers the base of the intake with brake cleaner multiple time, no signs of leaks. I've had the smoke machine hooked up 3 to 5 times and again no signs of leaks. At this point what is the best route to take? Remove intake manifold so it's easier to get to and replace the main grounds behind the heads and replace gasket at the same time? Replace the pcm? Replace throttle body maybe? Any other suggestions or recommendations would be greatly appreciated.
  17. Good Evening, Gents. I hope all is well. Let’s get started with a little introduction of myself. My name is Cody and I’m new to this forum. I’m a long-time active member of other forums with previous vehicles. A year and a half ago I traded in my 2001 Z06 for an 07 Silverado. Extended cab, Flex Fuel 5.3 with 78,000 miles. 1 owner and a VERY well maintained vehicle. The truck has done me very well and is extremely dependable (duh; Chevy and the 5.3). About 4 months ago I started having a random misfire issue when traveling between work and home (~300 miles each way on the weekend). I had a minor misfire/hesitation and a check engine light. It wasn’t flashing, so I drove into the next town and had it checked. It was a p0352 and p0300 code. I got to my trailer where I work and changed the plugs and coil pack that it was indicating was the issue. It cleared up for a bit and then the p0352 returned. I swapped the coil pack with a different cylinder, along with the spark plug wire as well, and the CEL return. Same code. I’m sort of at a stump for what it could be as some people have said ground issues, wiring issues, etc. I’ve always been mechanically savvy and have maintenanced my own vehicles and have repaired/modified them. I’m really just seeing if anyone has had a similar issue and what their outcome was. The truck has a very intermittent miss. Sometimes it drives and runs great, then out of the blue with stumble and fall on its face. It’s very inconsistent. Any insight would be awesome. Thank you so much.
  18. So I had a few after market parts installed on my 2015 Silverado: Flowmaster 40 series, Volant cai and finally some Gibson performance headers (heat wrapped and all). I didn't have any issues until the headers were installed. Shortly after leaving the shop my truck isn't shifting correctly and my engine light is on. I figured over heating was the culprit and that I should let it cool down before taking it back out for some fun. Hours later the problem is persistent and my truck is down shifting at too high of rpms causing it to jerk and stall for a second. I also feel like there's some power loss. I plugged in my Diablo inTune i2 and it showed the error code being a 3rd cylinder misfire and rough idle. I checked all of the spark plugs, the wires and all the bolts but I can't see an issue with any of them; all the plugs tested good and all the bolts are secured. Does anyone have any insight as to what the problem could be?
  19. I know I've seen post similar to this got a 2014 chevy Silverado 5.3 with a lot of issues been thru two different dealerships in last week. Truck was stuck in limp mode they replaced coils fuel injectors amf lifters and the modular that kicks it into 4cyl mode....now it still shifts hard (like it's in limp mode still) does not go into 4cyl mode at all and vibrates between 1300 and 1700 rpm range along with my dash looking like a Christmas tree with all the lights on ....just hit 70000 miles...everytime they put it back together there is another issue with another cylinder....any suggestions would be appreciated
  20. Hi guys and gals. Just recently got a 2003 Sierra 1500 4.8 4x4 z71 extended cab with 300,000km on the clock. Ive been noticing it hard on gas and idle isn’t really smooth, especially when it’s colder sometimes I can see the tac jump a little. When it’s cold sometimes the engine light will flash for a few minutes. But when it’s cold sometimes the fuel gauge goes to empty and sets the gas light on and then comes back to normal after a minute or two. Use to have issues with four way randomly coming on, but that stopped for now so far. So so far I have swapped two different fuel pumps (both came from tested and running parts trucks) , new ngk wires, new ac Delco plugs sometimes you can hear what I think is a sparking noise from the passenger side. I dont have a lot of money and trying to fix this without a garage. Any help be greatly appreciated. I hooked up my phone and torque app and have attached the error codes and some data the app gave me. I just dont don’t want to be throwing parts at it trying to guess what’s wrong. Thanks for your time!
  21. Hello, I looked 2008 GMC Sierra 1500 that I was interested in purchasing with the 5.3L V8 has 174,000 miles. Truck runs rough at idle, rpms are fluctuating. Check engine light is on with codes P0300 and P0301. Can’t troubleshoot the problem. Coils, spark plugs, spark plug wires, new O2 sensors, new catalytic converters. Guy says that rockers all move so it isn’t Active Fuel Management lifters and he says 150 psi of compression across all 8 cylinders. Truck was at dealership, dealership says problem with cylinder numbers 1 and 8 the P0301 explains problem with cylinder 1 but why isn’t code P0308 being thrown? What else could be the problem?
  22. My 2008 5.3L 4WD Avalanche with ~135K miles has recently been throwing a P0306 cylinder 6 misfire, along with a Stablitrak warning. It first happened a couple weeks ago but only lasted a day. I cleared the code and it was fine for another couple of weeks before it happened again today. It does go through a lot of oil (probably a at every 1,000 miles), and there is a clicking sound. I know from researching this the last couple weeks that its likely failure of the #6 cylinder lifter and/or plug fouling due to the AFM system design and/or old PCV cover. I intend on doing some diagnostics this weekend including inspecting and replacing (if needed) plugs/wires/coils, doing compression tests, and pulling off valve covers to look for stuck lifters/valves. My questions are: 1) Other than the obvious, is there anything else I should be specifically looking out for when running these tests? 2) Are there are any other diagnostic tests I should be doing while I am in there. 3) Assuming compression test is fine, and replacing plugs/wires stops the misfires, can I hold off on replacing a bad lifter if there is one? 4) I would plan on getting a Range tuner to disable AFM (which I should have done when I bought the truck 3 years ago) and replacing the valve coverwith the new one. If the compression test is OK suggesting there is (currently) no ring, gasket, valve, etc. damage, would these measures stave off more issues? 4) If a lifter is bad and I really need to replace it now, can I just replace the one, or do I need to replace them all? Also, how difficult is it to take the passenger side head off to access the #6 lifters? 5) If it does fail compression, am I likely screwed and looking at a rebuild or replacement? 6) Any other advice, recommendations, or thoughts? Thanks in advance!
  23. Hi guys, I need some help. On Thanksgiving I had remote started my truck to go make the last minute run to the supermarket. As I left my house to jump in and take off, I found the truck’s engine had stopped. When I started the truck with my key, the check engine light was on. I took it over to my local dealer and after a week and a half, I was told my aggressive treads (Nitto Trail Grapplers) could be the cause. The work order stated the tech swapped out my wheels and tires for a set of factory wheels and tires and could not get it to misfire. The work order also stated that code P050D was found. I did read in several treads this has come up and injectors was normally replaced. My truck was purchased in Oct 2014 and had 25606 miles on it when I took it in. There are a ton of lifted, leveled, stock trucks out there with the same tires so was wondering if anyone else had this issue. It’s really hard to accept that my tires (which has been on since 2014) is the cause.
  24. How's it going, I have a 2000 single cab 4.8 Silverado 1500 that has a misfire, gradually revving up the engine you can tell the engine is missing and causes truck to vibrate, and vibration is worse while driving. Has following codes: p0300, p0137, p0141, p0157. I believe these are codes for random engine misfire and various 02 sensors? If someone could point me in the right direction I would really appreciate it thanks
  25. New to site but I've got problems with my work truck I recently bought a long block 5.7 vortec from summit. And I also bought the updated fuel injection setup I also replaced the fuel pump the mass air flow sensor and fuel filter. It ran about thirty min. And developed a hesitation when I come to a stop then I would have to feather the throttle and it eventually would snap out of it and accelerate normally. So today I drove about twenty miles out to a place I ride dirt bikes and it was the same thing hesitated at every stop light until I got back into town and stopped at the only light and then it started missing and sputtering instead of hesitating and it is strange because it idles fine soon as I try to give it gas it starts dropping one or more cylinders and it doesn't stop missing I checked the wires and distributor cap rotor they looked perfect I did replace the distributor when I changed the motor also so it has maybe 3000 miles on it as well as the motor fuel pump water pump. I just changed the mass air flow with a new one last week. It's not showing any check engine light but I can barley get it to go. It misses so bad if I give it more gas pedal I intermittently back fires through the intake sounds like I'm am stumped I check the grounds I checked for vacuum leaks I need to get this thing running it's the only thing I have to drive for work. And I took last week off to fix the rear axle and put new brakes on the van along with new fuel filter and. MAF SENSOR. Please if someone can help it would be great to have this thing fixxed so I get my jobs finished thanks
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