Jump to content

#7 Cylinder Misfire

T-Town-Z

By T-Town-Z
in Troubleshooting & Recalls

 Share

Recommended Posts

  • Replies 37
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

newdude
newdude

I wish I had one of these trucks to test that myself. I do recall GM having some mention of oil aeration in their AFM lifter bulletin for these engines.   To me...that says 0w20 and maybe those

T-Town-Z
T-Town-Z

Here we go again !   4 years and 85,000 miles ago, I had the #7 lifter fail and had it covered under the power-train warranty.  Now I'm at 139,000 and it looks like I have another #7 AFM lifter failur

Brandon Lynch New Member

Brandon Lynch

Posted
Posted

I too have 2015 Silverado.  I just got my truck back from dealer had a collapsed lifter #7 at 65k. It ran great for two days tell I hit the passing gear it started popping and went back into dealer and I took the Mechanic for a ride and #7 failed again also thinks the vlom is bad so I'm in a loaner for a while I'll post more info as I get it.

  • 2 weeks later...
Brandon Lynch New Member

Brandon Lynch

Posted
Posted

Ok I got my truck back today the afm lifter on #7 came apart and ended up bending a rod. They replaced the rod, afm lifter this is the third one in less than 100 miles and they replaced the vlom. It seams to be running great right now and I put a range device in so hopefully I won't have anymore problems.

  • 10 months later...
TigerTW0014 Enthusiast

TigerTW0014

Posted
Posted
On 5/23/2018 at 11:41 AM, Glen Kierstead said:

Had this same thing happen to my 2014 5.3 LT Z71 with less than 37k miles on it. Happened to me yesterday. CEL Flashing with the Stabiltrak light solid. Start ticking even while pressing the gas. Rough idle and just running and sounding like dog crap! Called and scheduled a service appointment on it today for tomorrow at 7am. My code reader just showed P0300. Will update on what I find out over the next few days. Really disappointing tho. Almost want to just fix it and then sell it!!!

Can you update on what the issue was? I'm having exact same symptoms, #7 5.3 '14 112k afm tuned out.

  • 1 month later...
JHall- va New Member

JHall- va

Posted
Posted (edited)

09/23/2019:

 

Similar issue here, recently...P0307 Code/ Engine Light...  

 

Was told by my local GM Dealer - that they would NOT rebuild the engine, and that they would only "replace" the engine with this issue...well over $7,000 to do this!

 

My #7 plug is "Fouled"...causing the mis-fire and is in fact leaking oil.     

 

Unfortunately, my truck (2014 Suburban) has 86,000 miles on it - and NOT under Powertrain Warranty!   

 

Any advice?? 

 

thanks - John

Edited by JHall- va
  • 1 year later...
Skeeterhawk Enthusiast

Skeeterhawk

Posted
Posted
On 6/4/2021 at 1:04 PM, Charlie h said:

Im just staring to have the same problem at my 2017 z71 with 39,865 miles...

Well my 2017 only had 28,500 miles and had all injectors replaced and didn't fix the problem. Was spitting out P0300 and P050D codes.  Dealership just changed all the lifter. They are in test drive mode now. If this fixes the problem I'm selling the truck and getting a Ford. This is the right time to sell anyway. The dealership also told me they are still having lifter problems in 2020 trucks . Bye, Bye GM.

  • 4 weeks later...
T-Town-Z Enthusiast

T-Town-Z

Posted
  • Author
Posted

Here we go again !   4 years and 85,000 miles ago, I had the #7 lifter fail and had it covered under the power-train warranty.  Now I'm at 139,000 and it looks like I have another #7 AFM lifter failure.   But get this, I tuned off the AFM at 99K miles, and it still failed !!!   

For a couple weeks before, I noticed that when on the highway, if I stepped on it hard and it downshifted, it would do a double backfire sound, kind of a stutter, then finally regain itself and go.  I had gotten gas at a station I've never used before and thought it was bad gas.  I added a bottle of fuel treatment and finally refueled.  Next day, I'm on the highway and go to pass a semi, and when it downshifted, it did the double backfire thing again, but this time I hear a sort of bang in the engine, then it stuttered, then the check engine light comes on, along with traction control light, engine vibration and reduced power.  I limped it into work and checked the codes and have  P0300 , P0307 & P0324 .

Luckily I live down the street from the guys that own Prevatt Automotive Tuning here in Tulsa.   Initial diagnosis is a dead #7 AFM lifter and hopefully nothing worse.  Now just waiting for my turn in their shop.

I'll update in a week or so once they open it up......   

  • Like 1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Gkistler
      2015 Sierra Denali L86 cyl 5 misfire at idle

      By Gkistler · Posted

      Hi friends - first time poster. I have a 2015 sierra Denali with 150k miles, I’m the second owner and she’s given me 75k of great service. I run a pulse AFM disable device. Starting Thursday when I exited the freeway after a short local ride it started idling rough, with an obvious misfire shake and was down on low end power.  I got it home and hooked it up to my scannner and found no codes but in live data a pretty bad misfire on cylinder 5. I replaced the coil, plug and wire with all new OE replacements (Delphi gn10165 coil, acdelco wire and 41-168 plug). It’s still behaving the same way after firing the parts cannon at it.   I know cyl 5 is a non AFM cylinder so I am not thinking this is AFM related but I’m kinda at a loss. injector? Bent pushrod? It’s running too well over 1k rpm to suggest those IMO. Has anyone chase this issue before and what was it? Any suggestions? 
    • zibzer2
      Pulsating Noise 4Cyl Mode

      By zibzer2 · Posted

      2017 Silverado L83 5.3l 6speed transmission Hello, not a new member but havent posted in a while and my old signup info isnt working so had to create a new account. anyways, I have an issue with my truck and hope someone can spread some light on whats happening: -when it goes to 4cyl mode it makes a clunk sound (but not when coasting or going downhill) -when in 4 cyl mode and under load it makes a load pulsating sound (not a tick). -goes away completely when in M5 gear or when plugging in an AFM delete. Im guessing it is one of 2 things but im not convinced of either to be honest. 1. lifter stuck in v8 mode 2. torque converter shudder realistically it doesn't seem like the TC as there is no physical vibration , and it never happens in v8 mode. but maybe? and wouldnt a lifter make a sound whether with load or not? any ideas let me know please. thank you!  
    • Chuck FB
      Some Assembly is Required

      By Chuck FB · Posted

      Which has made me wonder with the various engine failures of a few brands in the last few years, is it sub par materials such as lifters etc causing failures, or bearing clearances on the crank etc or perhaps bad designing of an engine physically or causing too much load on the components due to the hp/torque they can push out of them. Or is the oil viscosity and additive package of current oils or a lack of oil flow by an oil pump not able to supply sufficient oil at idle or under high load at low rpm. Or is it every item I listed that combined together has pushed the limits so far to the left that there is hardly a margin of safety left and add in some fuel dilution and too long of an OCI and premature engine failure is the result ?. 
    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      He is not saying that an SAE *W20 will have more viscosity than a *W40 due to MORE VII polymers. He is saying that although multiple *W40 may post in the PDS the same or similar 100 C and 150 C viscosities that the blenders choice of modifier TYPE and AMOUNT to get his chosen base to grade will not give identical real world viscosities in shear and at temperature. All will pass the SII test but not all will pass the 100 C HTHS (unpublished value) testing the blender does and relies on to get the required by law "percentage improvement' referenced to his last great work.    Tis the problem with the lie. Once told others are required to support it. 
    • PunchT37
      Parking Brake - Automatic Engagement Questions

      By PunchT37 · Posted

      I have a `25, 1500 that auto sets on incline. Never knew that at first. I have the electronic shifter. Just think if it didn`t do that? Unlike a mechanical shift that you can muscle out of park, how would you get this thing out? That would be a problem.   What I found out later is, I don`t have to push the button to release. Just put it in gear.   Setting parameters? Don`t know if it`s possible.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...