I'm trying to keep my 1989 740GL going and, if not for the Brickboard, probably couldn't afford to...So thanks in advance!

Now that the weather has warmed up in MN, we noticed that when we come up to a stoplight the idle drops to a stall, so you have to keep a little gas to keep in running. Normal idle is about 800-900 rpm. We have had this problem in warm weather, not cold. The first start after garaging the car usually goes fine, but it's after the car warms up that the idle problem starts.

Any ideas? I've managed to take on much bigger projects than I normally would to save costs--and they luckily have worked out. Before I pay a mechanic a lot of money to diagnose the problem, I was hoping to get some leads...

Thanks.