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Old 11-13-2012, 12:36 PM   #1
Registered User
Join Date: Jul 2009
Location: Columbus, Ohio
Posts: 1,025
My Ride: e46- 1999 323i
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?



Photo in Cleveland, Ohio
1999 323i - Totaled at 265,000 miles.
Now an e30 & e90 owner.
thefrog1394 is offline   Reply With Quote
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