Wacky Idle Cure

[ALS XJ]

OK: I have a '92 XJ Laredo 4.0 w/286k. Here was my issue:
Jeep would start fine...about 1 minute into idle, it would sputter (spew massive hydocarbon out of the tailpipe), then rev itself up to about 1200rpm. This process would repeat itself over and over. When driving, if I mashed the throttle, it would sputter and almost stall (pulling out into traffic got very dangerous). I replaced the TPS, IAC, completely removed the TB, cleaned it and replaced the gasket. Nothing.:bang: I then moved on to a Complete Tune-Up (Cap, Rotor, Plugs, Wires and Acell Super Coil). Would not go away.:sign0181:
THE CURE: O2 SENSOR!:beer:
A quick 5 min. fix...Jeep is back to normal...idle at 750rpm solid.
I hope this helps somebody out there!:D

[nickyg]

OK: I have a '92 XJ Laredo 4.0 w/286k. Here was my issue:
Jeep would start fine...about 1 minute into idle, it would sputter (spew massive hydocarbon out of the tailpipe), then rev itself up to about 1200rpm. This process would repeat itself over and over. When driving, if I mashed the throttle, it would sputter and almost stall (pulling out into traffic got very dangerous). I replaced the TPS, IAC, completely removed the TB, cleaned it and replaced the gasket. Nothing.:bang: I then moved on to a Complete Tune-Up (Cap, Rotor, Plugs, Wires and Acell Super Coil). Would not go away.:sign0181:
THE CURE: O2 SENSOR!:beer:
A quick 5 min. fix...Jeep is back to normal...idle at 750rpm solid.
I hope this helps somebody out there!:D

Thanks for the tip. Glad it's fixed, to me, There's no better feeling then a smooth running auto. I'm just curious, Did it throw a code?

[ALS XJ]

Nope...no code. That's what had me so baffled!:out:

[4.3LXJ]

The O2 sensor only generates a code when the heater in it or the wiring fails. If they just wear out over time, there will be no code, just a rich or lean mixture

[Mudderoy]

Can you clean it? I have two new O2 sensors and I'm having that press throttle and bogging problem.

[Minty]

O2 sensor was just messing with my idle as well! Glad I FINALLY found the cure...

[ALS XJ]

Didn't even try to clean it...it was old enough to warrant a new part. I used the Bosch sensor, $55. @ Auto Zone (owning a Jeep, I had $20 in frequent flier miles on my card)...so, $35.net...including a bottle of lucas fuel additive.