[bmw] re: FS: Stumbling 1991 318i sedan

[jkerouac <jkerouac@xxxxxxxxxxxxx>]

re:  FS:  Stumbling 1991 318i sedan:

Air Flow Meter wear is common on that style of AFM and with that many miles.
Particularly likely if the problem occurs with increasing frequency, and 
may be sensitive to engine temperature.
    A dealer computer won't know what to do with it since from your 
vintage it can only tell steady state conditions which have to be 
occuring while the computer is hooked up.
    Also, an engine fault won't occur when the stutter happens because 
the computer interprets the open connection between the pointer and the 
carbon pickup band as just meaning that no air is getting into the engine.
    No air means don't supply any fuel. and don't tripper a spark.  No 
fuel and spark is the cause of the stutter.  With engine RPM dropping 
due to the stutter, the pointer moves to a lower point on the carbon 
band with less wear, therefore making contact again, telling the 
computer to supply fuel again.
Point to diagnose:
When the stutter occurs, does the tach needle drop to zero?  IF so, then 
likely its the AFM that's your problem.
Good Luck,

'jk
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