The wagon this time....1991 240 approx 210k. I have replaced the engine coolant temp sensor, inspected the air inlet duct for cracks and rub holes and have checked the function of the throttle plate sensor, adjusted the idle stop, all appear to be fine. Here is the symptom. When I start the car, cold or not (outside air), the car idles very high. It does start to come down when it starts to get near operating temp. Then when I select either fwd or rev, it idles up again temporarily and will stay higher than normal while driving. Very annoying especially in town driving, stop and go. Then it will sometimes go back to normal.
Not sur what to check next. I have checked the archives and mostly see what I have done. Any ideas?

Thanks for your help...

Heidi, Sven and 500 (the name of the third 240 cause that's what I paid for him)