I have a1990 740 GL and when the car is in park the idle will rise to 1500-2000 and stay there no matter how long the car runs. But when I put the car in drive the idle drops down to 900-1000, which is normal. Also when the car is in drive the whole car will shake, not too bad, but enough to raddle thing around. There is no check engine light on. Im stumped. Can anybody shed some light on this problem?

 

it could be ur maf sensor. i had this problem with my high idle. make sure none of the wires have been rubbing and r no make contact. about the shaking i cant help u there

 

maf sensor?

 

I would imagine the throttle switch or linkageis out of adjustment. hopefully that's going to be the issue, probably is.