I had a problem where the idle was 1500-1800 in neutral & park, and about 1000 when in drive. Turns out it was an ECM of some sort...there is one on the front passenger side floor...I believe that is the one replaced. I get my car back tonight, so we'll see if it's 100% again, but word on the street is that it's fixed.

My idle tended to seem to be high only in warmer weather conditions or after I drove it awhile - and lately, since the weather has been warmer, the idle was always high. Cruise control didn't work when the idle was high. And once the idle was high, it wouldn't go back down under any circumstances, unless I restarted the car (and then it only went back down rarely).

My high idle started right after I had the throttle acutator replaced...not sure if something maybe got shorted when that was put in, or if the ECM was always screwed up and I just never realized it because the throttle actuator was also screwed up...

Not sure if this helps at all, but at least that's my experience from a similar sounding problem.

Matt
1994 E320
167k