I know this topic as been chewed up and around two dozen times, but I've read and reread the FAQ, performed as many checks as I could, and haven't found the problem.

I am trying to figure out what's wrong with my '89 740 Turbo Wagon, 110K miles. On cold and warm starts the engine starts fine, rpms revv up normally, but then as the rpms settle down, the needle goes down into the 500 rpm range, engine tries to catch itself, and dies. Then, the engine starts up immediately again, and as the rpms settle down again, the engine fights to keep itself alive, and usually succeeds on the 2nd or 3rd try. As the engine warms up, I have no problems at all idling, whether in neutral or in gear. Car drives like new.

Here's what I have checked so far:

Cleaned Throttle Body
Checked for Vaccuum leaks
Replaced Air Filter with OEM filter

This morning I tackled the AMM. I removed the connector, setting the car in limp home mode. When I started the car, the rpms obviously jumped all over the place, but the engine didn't die as it would usually! I moved into gear, engine didn't die. Then I put the AMM connector back on, started the engine, and moved into gear - the engine died. Have I found the culprit? Or is the fact that I was in limp home mode overriding any other problem I may have?

Please help me out over here - I don't want to replace a $200 AMM without good reason. Thanks in advance.