RPM Drop

[Focusva]

I'm having an issue and I'm lost for ideas. I own a 2008 Explorer XLT 4.0l V6 with 70k on it. Had the transmission replaced under warranty with a rebuilt unit around 63k. Now when I start the car the RPMs jump up to 2k RPMs for about 30 seconds then back down to 600-800. Then as I come to a stop the RPMs drop to 500 every time unless I'm in stop and go traffic or come to a stop extremely slow. I cleaned the MAF and it stopped for the next two trips, but then it started to drop again. I'm not getting any codes. Any help is greatly appreciated. If this was my SVT Focus I'd have this thing torn apart but I kinda need this as the kid huller.

 

[Ornery]

Wouldn't cost anything but time to clean the Idle Air Control valve. Worth a try...

 

[Focusva]

I'll try that today, also gonna clean the throttle body as well. Thanks for the link to the how to.

 

[Flag Gibby]

I believe I had something similar to your symptoms years ago and I had gotten some really dirty gas and plugged up my fuel filter to the point that I burned two of my sparkplugs (I was running so lean on the second bank that my MPG was really good). I would say pull your plugs and make sure that they all look like they are firing correctly and show no excessive wear and if you haven't done it replace the fuel filter since it is due at 60K.