For.my son's 04 Silvy 4.8, approximately 180k km. It starts and runs fine until you give it a bit of gas, I'd say just above 1/3 pedal, and it will have misfires in the odd side bank. It will flash the CEL as it's happening and will eventually set P0300. Things that have been done so far:
- swapped coil packs from bank to bank
- swapped plugs
- swapped injectors
- checked for vacuum leaks with Carb cleaner, nothing
- compression test, all 160-170psi
- fuel pressure good at 60psi and holds it even under load
My son monitored the misfire data using the Tech 2 and it would misfire on 1, 3 and 5. Funny thing though is that he swapped in a spare PCM and it was now misfiring 1,3 and 7.
The plugs all looked good, if anything, slightly cleanish with a partially white/brown porcelain.
Next things I told.my son to check is wiring and grounds. He's very technical and is currently studying heavy diesel tech as well as following my footsteps. I'm also at a loss.
Any ideas of other avenues to follow?
- swapped coil packs from bank to bank
- swapped plugs
- swapped injectors
- checked for vacuum leaks with Carb cleaner, nothing
- compression test, all 160-170psi
- fuel pressure good at 60psi and holds it even under load
My son monitored the misfire data using the Tech 2 and it would misfire on 1, 3 and 5. Funny thing though is that he swapped in a spare PCM and it was now misfiring 1,3 and 7.
The plugs all looked good, if anything, slightly cleanish with a partially white/brown porcelain.
Next things I told.my son to check is wiring and grounds. He's very technical and is currently studying heavy diesel tech as well as following my footsteps. I'm also at a loss.
Any ideas of other avenues to follow?
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