I've finally figured out what the problem is with my newly bought '92 BMW 535. The air flow sensor is messed up. I removed it and measured the resistance while opening the vane and it wasn't linear at all. Closed it was 680 ohm, opened a little about 1100, almost fully open 110, and completely open 420 ohm. I cleaned the circuit board and readjusted the pick up to get 1100 ohm completely closed and then the drop was pretty much linear, except for a few spikes up to 900 ohm, down to 100 ohm at about 70% open. More than 70% the resistance would increase and at about
90% it would go off the circuit board and into infinity. Figured if I drive gently I'll be okay until I get a new air flow sensor. I thought it would be best to reset the ECM too, so I removed the minus cable off the battery and waited a while. However, now the car runs *really* rich and the idle will oscillate until it stalls. So far I've only driven for 10-15 minutes, but how long does it take before the ECM relearns what it needs to know? Also, what should the resistance be for the air flow sensor, and is it possible to buy a new circuit board instead of the whole "box"?Ulf