88 cherokee hi idle

[mikkyle]

Hi,
Ive had an ongoing problem with hi idle in my 88 laredo 4.0, since I got it 6 yrs ago. Usually I spray some cleaner down the throttle body and sometimes have to remove the AIS sensor thing and spray cleaner in that bore too. It usually works great for a couple months and then I have to do it again. Well this time it didnt. In fact it idled even higher than before. (around1800 RPM) I replaced the TPS no fix, Replaced the AIS sensor right next to the TPS, no fix, still idling around 1800 RPM. Since then I've read somewhere on a forum that you shouldnt use carb cleaner on the throttle body and/or the AIS sensor, that it removes the teflon coating. Oh well, too late. Or is it?.
Anyone having the same problem?
Do I need to buy a new throttle body too? I dont care, whatever will fix it, Im wearing out my u-joints and brakes, and my wife doesnt want to drive it. Help.
Mike

[Dukes69]

Hey Mike,
You've replaced all the sensors that I thought would be causing the problem. Just for fun, you might want to take the throttle body off, disassemble it and clean it out with some carb cleaner. There could be some junk caught in one of the passages. In addition, check for vacuum leaks. Good luck.

[CherokeeFever]

Have you checked and cleaned off the CPS located at about 2 o'clock on the flywheel housing on the motor? Most Jeeps with this problem in the 87-90 year range suffer from CPS problems.

HTH and GL.