[shawntech]

N54, 94k miles, new plugs 4k ago, intake valves walnut blasted (this problem didn't change)

The car runs a bit rough cold, no misfire or other faults, no drivability problems once warm.

Never liked that the trims were apart... at idle they are b1 -3.3%, b2 +5.5% and that ~8% follows WOT as well.

Also checked injector calibration numbers they are correct, are the rough cold starts and trim separation related? I've been told to just replace all the injectors but I'm hesitant since I can't prove one bad.

I removed PCV valve and checked operation, seems fine, also checked breather hose flap etc, cannot find any problems.

[Jklad]

I had rough cold starts, they were inconsistent. I was thinking injectors, even thought they were new. But, a new hpfp fixed this issue. The car no longer rough idles or bogs on cold start, and fires up much quicker - 2to4 cranks only. If yours is cranking longer than that, look to the hpfp. Also, I was throwing p2b2c on occasion.

[shawntech]

mine starts on 1 or even less than a full crank, consistently, holds fuel rail pressure overnight no problem... HPFP was replaced with 4 fuel injectors in 2011 under recall. I have no reason to believe I have a HPFP problem since there's no faults, but I have no way to "test" it either :/

[shawntech]

bump, left it off all weekend... started with this shakes this morning and stuttering a bit between shifts til it warmed up for a mile or so... no faults still wtf