strange idle

has anyone experienced this. when i start my jeep it revs up to 2000rpm right away then drops down to 1500 immediately, then drops to 1000 and even down to about 800 then slowly levels out at about 1000-1100rpm.after driving it for a while it drives nice but when i shift down to first to stop and push the clutch all the way in to stop it jump up to 1250rpm sometimes even around 1400rpm, and stays there while i'm holding the clutch. by the way, its a 88' 4.0L 5speed. i lust replaced the manifold temp sensor, coolant temp sensor, oxygen sensor and knock sensor, and i adjusted the throttle position sensor to about 17% give or take. whats up with this???

oh, also, what should my jeep normally idle at. 1100rpm seems kinda high to me?

It should idle around 700, from my experience it still seems there is something wrong with the tps. Sometimes there can be a dead spot at a certain throttle position and mess things up. I checked the renix manual, and you're correct that the input voltage should be 17% of the output voltage.

yeah, it seems like i have done everything with the sensors and emmissions stuff and still my mileage is poor and it idles high. i love my jeep but it really drives me carzy!!!

May be you have a vacuum leak, I know the manifold bolts work there way loose once in a while.

maybe.... i am missing the very front exhaust manifold stud(it snapped off). but i haven't checked the intake maifold bolts for tightness. are they hard to get at?

I can get to most of them with a box end wrench, and taking the air filter box out for better access.

k, i'll try that. i'm really getting sick of 12mpg after all the money i've poured into this heep trying to get better mileage!!! i'm sure there are alot of guys on here feeling the same way as me though.

anyone else have some input?