Okay, here we go again. After sorting out the cold start issue on my girlfriend's 190e, there's been an intermittent problem with the idle. It certainly idles too high, around 1000-12000 rpm. Also, on hot days, there is often an idle surge of about 200 rpm. When the car is first started, it idles at about 1500 rpm and settles down after a second.

I have some experience with CIS, but none with CIS-E. There's seems to be more than a few differences between the two systems.

On this 190e, when I unplug the connector to the IAC, there is no change. On the CIS cars I've owned, the unplugging of that connector would usually cause an idle jump to 2000 rpm. Is this not the case with a CIS-E car?

Also, when I pinch the vacuum lines running to the IAC, the car stalls out. So I'm guessing the IAC isn't closing. Google searches have pointed me to the AFM potentiometer. Is there a test that car be done to the potentiometer?

Any help/advice is welcome and appreciated.