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Starts fine, rough after a minute, then runs fine again

Xj_idget

NAXJA Forum User
Location
Cincinnati
My 2000 Sport, 4.0/AW4, has started behaving oddly:

1. Starts fine, idles fine
2. After about a minute or two it starts to idle rough, run rough, lose power
3. Then after another minute it slowly clears and begins to run fine
4. Continues to run fine until the next start

- It does this regardless of whether it is a cold or hot start.
- Does it every time, sometime to varying degrees, but everytime.
- No check engine light

Any ideas what I'm dealing with here? TPS? MAF?

Any help much appreciated.

Thanks ~ Steve
 
Fuel pressure issues are unlikely, unless there is some heat soak or vapor lock. It is easy to test fuel pressure.

It sounds like you are describing some sensor issues that occur when the the Jeep switches to closed loop operation.

Test the O2 sensors, they can get old and slow to react. Typical O2 sensor service life is about 100,000-150,000 miles.
 
X2 on the possible O2 sensor. Check the heater voltage to the O2 heater, and the resistance of the O2 heater, and the O2 wires for physical damage. Then test the O2 sensor signal.
 
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