Deviation rich (both banks), rough idle
I am getting codes for lambda adaptation deviation rich in both banks. I also have an idle drop problem (engine idle RPM will drop and feel like its about to stall before recovering).
I tried unplugging the MAF and the idle drop issue seems improved but not completely solved.
I tried spraying carb cleaner near vacuum leak prone places but found nothing (near intake boot, CCV). Also, wouldn't deviation rich indicate that it is NOT a vacuum leak? (That would cause deviation lean, right?)
I am ruling out O2 sensors since it is both banks. Good assumption?
This leaves in my mind just the MAF sensor itself. I would rather not spend the money to replace the MAF sensor unless I am pretty confident that that is the problem. This is on my 01 330Ci. I also have a 99 323i, anyone know if these MAF sensors are interchangable? Appear to be different part numbers on realOEM so guessing thats a NO.
Anyone have any input for further ways I can diagnose without beginning to throw money at the problem?