So, I am driving on a long trip with my 2002 Durango 4.7L with 89000 miles and I am going up and down hills in upper Michigan and my tach is going crazy ... With the cruise control on, every time I come near a hill the trans would seem to slip. I would have to shut off cruise and take control my self. My tach would still fluctuate 200 to 1000 rpm as I worked the pedal, I would switch OD off to get up the hill then it would still fluctuate going down the hill. Didn't fluctuate with OD off going up the hills ... It was also using a ton of gas while doing this.

We stopped at a rest stop and started out again and it did it a few more time then the "check engine light" came on and it stopped. It still would do it a little bit under my control but just about 200 rpm. When I tried to turn cruise back on it would go right back to doing it. I drove 200 more miles to get home ... anyone heard of this happening? is it my trans going or something electrical?

It seems to me that something could not detect wear the pedal was?
I kept thinking my trans was going but it would not have made my 700 mile trip if that was so. Fluid level is fine and color is close to right ...

 

First things first. Get CEL CODE read Most Advance/Autozone should read for free. Post code then get back to us. try to get a print out of the code reading, they usuallu include possible recommendations for repair.

 

mine did the same after a tranny rebuild and it turned out the TPS was going bad, not bad enough to toss a code out but bad enough to get the 200-1000 rpm surge... thought they messed the tranny rebuild up at first.... TPS is like 40 bucks and a cheap fast way to see whats up.

 

Well, I went to Autozone and had the code read, it was a P0121 .. Throttle Position Sensor Malfunction. I bought a new one for $31.99 and replaced it in a jiffy. Yep! it was the problem! Once I put the new one on and started the engine even my idle changed. I have had a erratic idle for sometime now. Now it's back to the way it's suppose to be ... thanks guys for all your help! Wish I would have known BEFORE my trip ..live and learn! ...

 

glad it's sorted, and the first I have heard of the TPS toss'n a code in my search to fix mine.

did you reset the ecm? it needs to relearn now, if not it's covered in the howto stickys.

 

Yep it was the TPS.

Remember to reset the PCM. There is instructions at the top of this post and also instructions to get the codes off your 2002 model as it has an on board diagnostic OBD-II feature built in from the factory so you can pull your own codes with out having to take it in! https://dodgeforum.com/forum/1st-gen...ine-light.html