high idle/o2 sensor

[skullfisher]

89 jeep cherokee was idling higharound 3500rpm. I replaced the IAC and it still went high, then i replaced the TPS and it works fine. When starting it idles at 1000rpm then slowly warms to 1500rpm and tops out at just under 2000rpm. I have checked for vacuum leaks and found none.So i changed the O2 sensor and now everytime when it starts and warms up it almost stalls 4 times, than runs fine at just under 2000rpm. Sounds like maybe the ECM isn't picking it up. How can i reset the ecm so it picks it up? i unplugged battery and had no luck. sure could use some help on this one. thanks in advance.

 

[SteelHeadz]

The battery disconnect should reset the ECM. Recheck the TPS and make sure its clocked on a full counter clockwise position. Although most of them are not adjustable, the TPS has a minute movement on its mounting hole and it's enough to make a difference on your idle situation. Disconnect the battery for 5 mins.. Reconnnect, then with the key on engine off, slowly step on the gas pedal all the way up to a wide open throttle then slowly release. Do this 2 times, then turn the key off then start the engine. If the high idle still exist, there has to be a small vacuum leak on the manifold or one of the lines hooked up to it.

 

[Bounty__Hunter]

I would adjust the TPS with either a digital voltmeter or an engine diagnostic computer.