Oxygen Sensor Issues

The diagnostic code states that the front O2 sensor is bad. Actually, 3 codes showed up (I don't remember them off the top of my head). I have replaced the front O2 sensor, checked for any bare wires (and taped up the rear O2 sensor wires that were exposed, and replaced the "relay/fuse" in the engine compartment fuse box. The check engine light keeps coming on though. The Jeep will idle inconsistently when the light is off, then the light kicks on and runs smooth. If I drive it with the light off and pull up to a stop sign, and press the accelerator to start moving again, it will sometimes act like it is "bogged down" and will not be responsive. It will then make a "clicking" sound and start going again. Anyone have a clue what the heck is going on? My only thought is that maybe the rear O2 sensor is bad too? Any insight would be appreciated.

Thank you

A bad rear sensor won't cause anything but a check engine light. It's just there to verify the cat converter is working and does not affect the fuel mixture. It sounds like there is still an issue with the front sensor.

What year, engine, etc we talking about? Some years in the Calf model have more than two sensors as well.

Knowing the codes would be helpful too.

Duckfan1 said:

The diagnostic code states that the front O2 sensor is bad.

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No, it doesn't. Codes very rarely indicate a hard part failure. They indicate an area that is not supplying the correct feedback to the pcm. Whether this is due to a wiring fault, part failure, or computer problem is the reason for diagnostics instead of just hucking a part at it.

lawsoncl said:

What year, engine, etc we talking about? Some years in the Calf model have more than two sensors as well.
Knowing the codes would be helpful too.

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Gotta start here......

It is a 2000, 4.0, AW auto, 4x4, 166k miles...

JJacobs said:

No, it doesn't. Codes very rarely indicate a hard part failure. They indicate an area that is not supplying the correct feedback to the pcm. Whether this is due to a wiring fault, part failure, or computer problem is the reason for diagnostics instead of just hucking a part at it.

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O2 sensor diagnostics by the ECM, for an '02, probably set codes for "sensor voltage too high", "too low", "signal not varying across .45v", or a sensor heater related malfunction. Each of these failures could be caused by parts failures that are only indirectly associated with the sensor itself. As an example, a leaking injector may cause such a rich mixture, that the O2 sensor stays above .45v, causing the ECM to "think" the O2 sensor is faulty.

Any idea on how to figure out if it actually is something else that is causing the issue? If it is an injector, where do I start troubleshooting that? Also, this morning on my drive to work it started acting up again. I pushed the accelerator and the engine would "bog down". I turned it off and started it back up, and the check engine light went off and it drove fine.... I am confused!

Duckfan1 said:

I am confused!

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So are we....until we see the actual code numbers. Get them read and post them here for comment.