i recently bought a '99 trooper. it has developed an intermitent high idle problem. sometimes it runs fine other times it will idle around 2000 rpm. I took it to an auto parts store and had the code read, it indicated an o2 sensor problem. I replaced all 4 sensors, and no change. I took it to a mechanic and he says its either the throttle position sensor (TPS) or a computer problem. he says the TPS is reading 8 volts at normal idle and 4.7 volts at high idle (ithink tose were the numbers). I replaced the TPS and on part of the test drive it kicked into high idle. i shut it off and on start up it was back to normal.........any suggestions?

 

Well, I may not need help after all. Since my test drive I havent had any problems with high idle. knock on wood, I think it's fixed.