I had the good fortune to locate a new Air Flow Meter from an ’94 964. The new AFM improved the low RPM response (off-throttle coasting) but my idle is still rough. I found and fixed bunches of vacuum leaks (false air)… (I decided to replace the intake gaskets -on order form the Host)
Many of you may know that it is quite possible to refurbish the AFM (redirect the rheostat sweep-arm to a new track). I recall seeing a write-up about this on the 911 List. Below is how it looks (on my now back-up unit) -note how deep are the old grooves (pitted ~ idle range -not seen) in the ceramic substrate. I repositioned the sweep to a lower (virgin) track, which makes this unit good for another 100K miles.
Tested the output voltage and was pleasantly surprised to see how (after all these years) linear (flap angle 0-110 deg) it actually is (!)
