88 D100 issues

We all like work-arounds with the problems of the computer controlled cars.

If the IAC and IAC circuit is inactive, that could be a good thing.

Just screw the IAC plunger bolt in or out to manually, permanently set your idle speed to 800 rpm. Run it like that.

If the engine wants to run on (dieseling) when you turn off the key, just put it in drive when turning off the key, that will shut it down.

At least it will run nice and idle nice when it is running.