jeep that revs at idol

my 93 cherokee with 205k miles, drops low in rpm's at idol or at a red light. then it revs back up to 2 grand. when in drive it wants to drive away with my foot on the brake. I have no idea what could be causing this. I also have another problem that I do not know if it is related to the first. on the road at 2500 rpm's the jeep suddenly makes a bad clunking knock that sound like its comming from the engine, and feels like it is stuck at that rpm. then revs up to 3000. it does it more often when I am low on gas. please help it sounds really bad.

hey,

i am 90% sure this is probably the problem - there is a Manifold Air Temp. sensor on the top of your engine manifold system (or should be - i have a 1990). Basically it helps regulate the air/fuel mixture according to your emission output. If you were to unscrew that and unplug it, you should see that the sensor is either clogged or stuck in the open position. It needs to be changed. Good news is it is a simple repair you can do yourself, the bad news is it will probably cost around 35-50 bucks for a new sensor.

They had trouble finding it at the parts store, for it is also called a Temperature air charger sensor, or a variation thereof.

that should do the trick...
good luck
jay

Bettin your problem is the throttle position sensor- is mounted on the front of throttle body, 2 screws holdin it on, they also cause auto trans not to shift out of 1st gear on auto trannies- will set you back about $60 bux. heard somwhere they had a recall for this same thing