Got a 2008 Ford f-250 6.4, truck came in with a very loud thumping noise, had codes p0281, p0269, p040d. I ended up pulling the cab and pulled the valve covers and found cylinder 8 exhuast rocker arm was off, we put 3 new injectors, new rocker arm, new push rod, 2 new turbos (had a pretty nice oil leak). everything else seemed to check out okay. I cleared the codes and ran the truck... still has a small thumping noise still and still throwing p0269 and p0281.. any help would be great as i have lost all my hair from pulling it out!!