2018 5.3 silverado misfire issues

[abaeza135330]

I have 2018 5.3 silverado, its been giving me code p0308 i already put in new injectors new high pressure fuel pump, and spark plugs and wires. Code keeps comming on and truck is really rough at idle and sputters when i floor it. Any suggestions out there?

 

[Hoesgottaeat2]

Does it have individual coils for each cylinder? I'd look there if you haven't already. Cylinder 8 sounds like the culprit here.

 

[abaeza135330]

I swapped it out with number one and spark is really strong got zapped while checking it even

 

[Hoesgottaeat2]

Know anyone with a real time scanner that can take the diag further? Hate to see you keep throwing parts at it.

 

[Fless]

Moved thread from OBS forum to correct year.

 

[Doubeleive]

check that the injector is getting a pulse on #8, what did the old #8 plug look like compared to the others?

 

[BlaineBug]

Did you replace the high pressure fuel lines? I heard they were ONE TIME USE only. Big pain in the ass to fix these fuel systems with the intake in the way requiring disassembly each time you need to do something and having to buy brand new lines each time that may or may not be available when you need them most!

 

[Mando6point2]

might be time to run a compression test on cylinder 8. Any noises along with the misfire? ticks/knocks?

 

[abaeza135330]

Thanks for all your help guys i found the problem ended up being a vacuum leak and a bad spark plug on cylinder 4 not sure why scanner kept telling me it had a misfire on cylinder 8 but problem was solved