AWD - idle uneven ONLY when half warm

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idle uneven ONLY when half warm 850 1996

Hi everyone,

Does anyone have any suggestions for the cause of this? When I start from cold, the engine idles smoothly. After about 5-10 min - just enough time for the temp gauge to get to normal and for me to get out of the neighborhood to the first light - the idle becomes unsteady: every 4-5 seconds, the rpms drop precipitously, only to recover quickly. After another 10-20 mins of driving, this goes away completely, and the engine idles smooth as silk for as long as I keep driving.

I recently had the throttle body cleaned, thinking it would address this, but no joy. I have checked for vacuum leaks, too. No CEL codes appear. I can monitor MAF, O2 sensor, vacuum, fuel flow, LTFT, STFT etc with Torque pro app. Nothing seems really awry. Seems like it could be some sort of temp sensor, since it only happens in a certain temperature range.

Anny suggestions would be greatly appreciated!


New idle uneven ONLY when half warm [850][1996]
posted by  jjmcc  on Sat Aug 10 15:39 CST 2019 >

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