I just returned from a trip to PA (approx. 1800 miles).I drivea 2001 Dodge Durango with a 5.9Liter engine. It has 70,000 miles on it. About 65 miles from home I noticed that while driving in overdrive the tach would surge a little and it felt as though the vehicle would shift out of overdrive for a split second and than back into overdrive. When I turned off the over drive the problem seemed to stop. However, when I stopped and placed the vehicle in park the engine would race and then go to low idle. Race, low idle! Over and over! It never raced over 2000 rpms but definitely was not running right. My question is this. Could my problems with the slight "slipping out of overdrive" be caused by a throttle sensor or something that is going bad and causing the engine to race as if I'm trying to accelerate? Would this cause the tranny to momentarily shift back to drive from overdrive in anticipation of the engine rpm increase? Any help would be greatly appreciated.

 

Gebby,

Please look into changing out your Throttle Position Sensor (TPS) as that is the likely culprit.

 

I agree with Kensai, it more than likely is the TPS, but try a couple of easy fixes first. Check all around the engine bay for a vaccuum hose unhooked. If everything looks good, give the throttle body a good cleaning. A can is only a few bucks at the parts store, and it never hurts. If the problem is still not solved, check the TPS. I'm sure there is a way with a voltmeter, I'm just not sure how.

 

+3 on the TPS.

What you are seeing Gebby is classic symptoms of a failing TPS. The part is ~$40, and is held on by two orthree torx screws to the throttle body.

As Jgaines said, checking for any possible vacuum leaks is a good PM thing to do, and it only costs your time. My money though is on the TPS.

Don