asilverblazer

You get yours when I get mine... if you need it back sooner, report it stolen.

Swap injector from a good cylinder to the bad one. See if the miss fire follows. Make sure they are legit GM injectors! Smoked CAT probably from running with the miss too long.

Slow down and start with the basics. There is nothing in the exhaust that is going to cause a miss fire. Try a power balance test, unhooking one spark plug wire at a time to try to isolate the miss firing cylinder. Use a scan tool and view cylinder miss fire counts to find a cylinder missing more than the others. If the above doesn't narrow it down. Check fuel pressure and the air intake track. A true random miss fire would be caused by something that affects all the cylinders. This rules out plugs, wires and injectors. On a 98 model there is no adjustment to the distributor. If you have had the intake off, I'd do a careful search for a vacuum leak at the manifold. Also, retrace your work to find an obvious fault like forgetting to reconnect something. Confirm that the only codes are P0300.

My 2015 5.3l half ton got exactly the same mileage as my 2018 L5P 1 ton. Empty OR Loaded The half ton was FAR more comfortable. The 1 ton is FAR more capable. So far the operating costs are essentially the same, except having to buy DEF. I value the capability more...

This thread smells strongly of boomers...

Great news, so now in hindsight, I've followed this thread but... What was the problem and solution summary? Clean all and replace one fuel injector and HPFP?

Changing the part isn't hard, it takes a while to get everything out of the way. You will need to be able to vacuum the system and recharge it.

Some would be nearly impossible. Hardware that mechanically improves towing capacity in the package would be the enhanced radiator and trailer brake controller, in some unique instances a two-speed transfer case might be useful, but not likely for highway use. You can add an aftermarket trailer brake controller easily. You could add a larger radiator, but I wouldn't unless conditions warrant it.

Twice on a GMT-400. We lifted it off completely and set it aside.

I wouldn't spend money on sensors until a diagnosis confirms they are faulty.

Seems reasonable enough to me.

I don't think I would do this, I doubt it fixes it... I'd focus on the fuel pressure signal first. There has to be a wire problem somewhere triggering the code.

Take a look at this: https://static.nhtsa.gov/odi/tsbs/2023/MC-10232712-0001.pdf

Before posting a poor review, are you dealing with the appropriate level of management at Les Schwab? I tend to agree with you that they have not taken a proper level of acceptance of their negligence. Whoever at Les Schwab that blew it off and sent you on your way seems to be the problem. I would expect more from the appropriate level of management.

What makes a nut a 'temporary' nut? IIRC, the upper ball joint nut has a flange up against the bottom of the upper control arm. I don't remember any means for locking them though. Where did Discount Tire come up with a nut? Did they run down to the hardware store and find something with the right threads? If the above is correct, I would have at least wanted a washer between the new nut and upper control arm to prevent the nut from marring up the upper control arm. I'm not faulting Discount Tire, I'm curious what they put on to determine then Les Schwab's actions below. Les Schwab should have replaced the nut with the proper type (if it isn't) and torqued it correctly, that was the liability they took on when they did the original job. I'm surprised that if the nut in question is noticeably different from the proper nut that they would wantonly send you on your way. Soooooooooo... If Les Schwab looked at it and made a (professional) determination that it was an acceptable nut (did it at least look like the right one?) and then presumed it was tight, you probably are good to go. Unprofessional of Les Schwab at a minimum. But I can understand a little bit of its together and tight, no harm no foul. Conversely, if it is obviously a hardware store nut; that's a problem they should have taken care of.

Each code will have a specific diagnostic procedure associated with it. Some codes indicate a problem with a sensor and require a sensor replacement. Some explain a condition that a sensor is seeing a problem with something else and the sensor is fine and shouldn't be replaced. Further, there is a common thought here that aftermarket sensors are inferior to factory, I'm not sure how often there have been documented cases of that actually being the case but it is also a possibility. The PCM expects to see very specific readings from its sensors and surprises or abnormal readings are going to cause problems, changing parts that aren't broken or replacing parts without a diagnosis can thus introduce new problems on top of the old ones - proceed with caution. Confirm the current code.

I don't think new sensors are going to fix that problem, I'd try to follow the sensor wiring to where they converge in the main harness then carefully examine from there upstream to the computer. The only way those two sensors are going to report identical voltage like that is if they are literally connected (via some problem) together somewhere. Unless someone else has some creative reasons why the PCM would see and report identical sensor voltages.

I would back track through your repair, could a section of wire harness gotten trapped under something and smashed? I wouldn't even necessarily start trying to diagnose a specific one of those codes. I think you'll find an obvious problem once you get in to it.

ECM's rarely fail and they even more rarely fail intermittently. Many parts you replaced are unrelated to a check engine light. Full tune up, what did this include? CAT, the engine has been running poorly enough for an extended period of time to kill the catalytic converter? O2 sensors, why? MAF, why? High pressure pump, why? What are the current trouble codes? Transmission coolant lines, air ride compressor, new struts, front shocks and coil springs are not related to the engine running poorly.

Start with the basics. Presumably everything is covered in mud. Clean it all out. Make sure no mud or water or other contaminates entered the air intake track. After everything is cleaned inspect all wiring connections that they are connected, intact and no wires have been chaffed snagged or burnt. Look closely also where the main connections to the PCM are. Disconnect the battery for a few minutes and reconnect to reset everything and report back any new codes. Getting stuck generates a lot of heat, since your actual speed is low it can build up under the hood and chassis. Mud can also get pushed places it shouldn't and can push wires and connections against hot surfaces they wouldn't normally contact causing them to melt or break. When the vehicle is close to the ground wires can also get snagged and pulled loose or unplugged. For now I would proceed as if there is no significant physical damage and the issues stem from the PCM not getting correct signals, all the codes indicate a problem with the sensor(s) circuit, they have either been unplugged or the wiring to them damaged. P0113 Intake Air Temperature Sensor 1 Circuit High P0118 Engine Coolant Temperature Sensor 1 Circuit High P0358 Ignition Coil H Primary Control Circuit/open P0361 Ignition Coil K Primary Control Circuit/open P0442 EVAP System Leak Detected (small leak) P0443 EVAP System Purge Control Valve A Circuit P0448 EVAP System Vent Control Circuit Shorted P0449 Evaporative Emission System Vent Valve/solenoid Circuit P1516 Throttle Actuator Control Module Throttle Actuator Position Performance P2135 Throttle/Pedal Position Sensor/switch A/B Voltage Correlation

P16E5 is the code for high fuel pressure. Obviously the number displayed is not correct. Check the connections on the fuel rail pressure sensor. Not displaying "OK" or "Not Run" limits diagnosis to circuit testing on the fuel injector. I suspect something isn't connected entirely, maybe a fuse, maybe disconnect the battery and reconnect. Maybe... the harness (or wire) to the injectors has been damaged and finally after messing with it this much has completely severed.

1. Either the sensor is no good, or inspect the wiring. 2a. The catalyst efficiency codes don't go away. 2b. Probably-open/closed loop is used regardless of catalyst efficiency.

Sure would like to be able to go way back and see miss fire counts from day 1, instead of chasing a P0300, I wouldn't be surprised if the one failed injector had a noticeable miss fire count higher than the others. I think you put all the original injectors in plus one to replace the failed one, you'll be good to go!

Based on my experience, I think the 4600 bilstein allow more motion than the 5100, this is contrary to internet wisdom that says they are exactly the same.

Only thing left to swap is an injector. Could be an intake gasket leak. Of course a proper diagnosis would lead to a coreect solution. Sounds like the dealer is convinced there is no spark in the cylinder. I would try to inspect wiring.