does anyone know what would cause a high idel at startup on my 87 xj pioneer sometimes can kick down sometimes not any sugestions please

something tells me that it could be the TPS, and I also have that problem. Except that I can't replace my TPS yet unti I confirm (need a voltmeter) that it's really gone bust. TPS costs somewhere between $40-70 I think. :)

Could be a lot of things. A bad sensor, vacuum leak, stuck linkage.

Does the idle return to normal eventually (like when it gets hot)?

sometimes it will idle hi when it is warm after you shut it off and turn back on

Could be a lot of things. A bad sensor, vacuum leak, stuck linkage.

Does the idle return to normal eventually (like when it gets hot)?
sometimes whaen it is warm it still idles high

Change the tps- mine started goin bad just enuff to fustrate me until that one day I dropped it into drive and w/o hitting the gas rpm's topped 300- dam near slammed a parked car. am 99.9% sure of this.

Mine has the same problem caused by the tps. i would clean it or get a new one.

On my Jeep this was caused by the idle speed stepper motor failing. I'd recommend getting a voltmeter to check the output voltage on the TPS before you replace it.

Well, first make sure you don't have a vacuum leak. Then the other responses have good suggestions on the sensors to check.

On my Jeep this was caused by the idle speed stepper motor failing. I'd recommend getting a voltmeter to check the output voltage on the TPS before you replace it.

Actually, the "voltmeter test" for me wasn't definitive. I had it checked twice, and also with the Chrysler computer and the TPS was still good (they say). However, people at this forum and jeepforum.com kept telling me it was the TPS, so I borrowed the TPS from one of the Jeeps at the shop and voila! IT WAS THE TPS...

So, my suggestion is, better than the voltmeter test, would be to borrow or try out a working TPS and see its effects. I think a TPS is solid-state circuitry inside and can be "wacky" - as in good this time, bad the next minute... What say you guys?!? :)

thanks guy i replaced the tps and promblem solved runs great now

Our pleasure :)