So, after parts arrived a few days ago, I decided to tackle the Engine Coolant Sensor and the Intake Manifold this afternoon. Took me about 4 hours because I also cleaned the AMM, cleaned the IAC, cleaned throttle body and new gasket, cleaned the PCV box, new air filter, and a new Fuel Pressure Regulator.

After taking all of those parts out, the manifold gasket and ECT sensor were pretty easy. A few tight spots, but everything went back together - thankfully.

Starts and runs much smoother, so I'm happy. It (1990 240) seems to have more power, and I'm looking forward to getting a new header pipe on (it has a leak) and a new cat to smooth it out even more. Doing this because every two years, the cars fails emissions and i have to put a new cat on too pass...

Here's my question. After taking it for a highway spin, I put it in park and the idle revs high and stays high... Is this a sign of a bad IAC? I cleaned mine instead of replacing it (I have the part and was going to return it) but now I'm thinking I should put the new one on.

Anyone know what the cause of a high idle after driving then putting the car in park?

bricker