ztlance

So about a month ago my CEL came on for a misfire in cylinder 1 it wasnt acting like a typical misfire i couldnt tell a difference in the way it was running at all. So i changed out all the plugs and coil packs and it went away for about 3 days or so. It then returned only this time it came back as a random misfire and then a misfire for each cylinder it was also running lean. but this time i could tell it was misfiring and it also seems sluggish. so i warrentied out the coilpacks and plugs changed them again and cleaned out the MAF sensor and it didnt get any better. So put in a new MAF sensor and cleaned out the throttle body and still nothing. and then all of the sudden it was running normal, no misfires at all and wasnt sluggish. and then about a week ago it came back. It still has the same codes coming up and im not sure what to do i kinda think it may be a turbo issue because when i do a cold start and it warms up the turbo briefly spools at 1200 rpm and i cant imagine thats a normal thing and once again its being sluggish. So turbo? redo plugs and coil packs? Fuel filter? Btw also checked wires for coil packs and fuel injectors nothing is cracked as i know this is a common issue also no suction from the fuel injectors. Any ideas will help. Thanks in advance!

John535is

Check for a vacuum leak. I just had the same, one day OK, then it would randomly idle up to 1200 rpm, then become sluggish etc. Can you do a scan with a VCDS or similar to get some codes?
Otherwise, I just pressure tested the vacuum system using a blanking cap in the air intake and some compressed air (check youtube videos on what to do) and this showed a leak in the crankcase breather tube. Also check the PCV valve, these fail and are harder to detect. I changed the leaking crankcase breather and the little PCV (#035103245G).

Rsniper4

If its not a vacuum issue, the next place to look would be the fuel pressure regulator and/or fuel pump.