Need help...out of control engine revving

I have a 1987 wrangler. it is a 2.5L 4 cyl throttle body injection and its got a 5 speed manual tranny. Ok well heres my problem....wether it be a cold start or a hot start my jeep will sometimes automaticly jump up to 3500 rpms and the only way to get it back down is to redline the engine and it will drop down and most of the time not back down to its idle...it will usally drop to around 1000 to 1500 rpms, and even after that once i start driving again and i press the clutch most of the time the rpms will jump back up to either 2000 or 3500 rpms. i have no idea how to fix this i was hopin for some help from anybody. Any help would be greatly appreciated! thanks alot

the throttle body probably just needs a good cleaning, either that, or the throttle cable is sticking.

well i dont think the throttle cable is sticking cuz the rpms jump up and down at random times without me touching the throttle.

Hey bud my 89 wrangler doing the same thing. A mechanic here in town told me it was my tps (throttle position sensor) sensor was bad. I priced it at 38 bucks and i am fixing it tomorrow.

yeah, probably a bad TPS or MAF (mass air flow meter) clean up the throttle body and see if that helps.

Well TPS's cost a bit more then $35.00 but your looking in the right direction. I would also replace the Crank Shaft Sensor as it is the part that tell the computers what speed the engine is running (or idling) at. They are not too difficult to replace and can be purchased at your local parts shop.

Please keep us posted on what your repairs are.