P0307 misfire on 2016 Silverado 5.3

[Jim74]

My girlfriend's '16 Silverado (5.3 engine) has been throwing a P0307 misfire but only above roughly 3500 rpm. Apparently she had to accelerate hard to avoid a collision and it had a noticeable lack of power and a check engine light came on. I scanned it to get the code and clear it, then took it for a drive and I was able to replicate the issue, then the check engine light would blink a few times then would go away.
I'd hate to think this is a collapsed lifter or something, though if it was, wouldn't it misfire all the time?
She just had her spark plugs and wires replaced at a shop (truck has 91k miles on it), so possibly an ignition coil? Injector?
Any ideas or advice is welcome. AFM is disabled on this truck, btw.

 

[twouvakind]

Double check the shops work first. Quite the coincidence.

 

[The Critic]

Symptoms suggest a possible valve spring failure. More investigation needed.

 

[Jim74]

Symptoms suggest a possible valve spring failure. More investigation needed.

oh, didnt think of that one, ty

 

[doublebase]

Blinking check engine light is a catalytic converter damaging event (fuel misfire). These trucks have had injector issues, along with lifters. With you also just having the truck serviced, there’s that possibility too.

 

[repairman54]

Pull the plug and look at it. Shop could have cracked the new one, anything is possible. New wire could be bad, swap it one over and see if miss moves also.

 

[mattd]

Being under high load/high stress and given the history of these engines I would perform a static and dynamic compression test. If you don’t want to do that, pull the left bank valve cover and bar the engine over and observe/measure rocker arm travel.

 

[stevejones]

Did the shop use ACDelco ignition parts or......something else???

 

[someonesomewhere]

Pull the plug and look at it. Shop could have cracked the new one, anything is possible. New wire could be bad, swap it one over and see if miss moves also.

This is where to start. Diagnose that the recent work/parts are good, then check the coil for that cylinder. Start easy before you start pulling valve covers and such as others are suggesting.

 

[Chris142]

Symptoms suggest a possible valve spring failure. More investigation needed.

That was my first guess

 

[Jim74]

Did the shop use ACDelco ignition parts or......something else???

ACDelco

 

[wtd]

To check for a possible compression problem, You can sometimes put the vehicle in flood crank mode by holding the accelerator all of the way down while cranking the engine and if the cadence of the engine doesn't sound even, it usually indicates some type of compression issue. This doesn't always work but it's something easy to try.

 

[clinebarger]

I would inspect for a cracked plug first. I see it often with recently "tuned up" Gen V engines.

 

[someonesomewhere]

I would inspect for a cracked plug first. I see it often with recently "tuned up" Gen V engines.

Yep. When issues like a misfire occur shortly after a tune-up that involves new parts, always start troubleshooting with verifying the new parts are good and were installed correctly.

 

[emmett442]

I just did a job on a '15 5.3 Silverado. P0305. I did plugs and wires first because it had 170k miles and had never been done, so it was due regardless.

Ended up being an injector though. Come to find out, it's much more common than in the old port injected engines. Plenty of TSBs for you to look up.

 

[GMBoy]

My experience has been these are usually going to be a lifter job but hopefully since you just had tune up it may be a bad plug or perhaps coil went out. I hope so for you! These engines have pattern failures with lifters and injectors.

 

[Drew7a]

Just did a 5.3L Owner took it to Chevy dealer for "Tune Up" had a bad miss and threw misfire code. Dealer said it would be a week before he could get back in. Scan Tool Graph showed cylinder 1, misfiring. Pulled plug it was gapped at 0.012.

 

[97prizm]

My girlfriend's '16 Silverado (5.3 engine) has been throwing a P0307 misfire but only above roughly 3500 rpm. Apparently she had to accelerate hard to avoid a collision and it had a noticeable lack of power and a check engine light came on. I scanned it to get the code and clear it, then took it for a drive and I was able to replicate the issue, then the check engine light would blink a few times then would go away.
I'd hate to think this is a collapsed lifter or something, though if it was, wouldn't it misfire all the time?
She just had her spark plugs and wires replaced at a shop (truck has 91k miles on it), so possibly an ignition coil? Injector?
Any ideas or advice is welcome. AFM is disabled on this truck, btw.

I had a Geo prizm that would do this every so many years. The #4 spark plug wire was closest to the engine and would be damaged by the heat.