I've just bought a 2001 slate grey Durango with the 4.7L V8.

I've noticed that it likes to bounce around RPMs when it's ideling (and sometimes during driving). It will usually idel around 600 RPM but sometimes it will randomly go up to 1200 down to 600, then 1000 (just an example). All this is happening before my eyes. Sometimes giving it a little gas will settle it back down.

I'm starting to think it's a sensor issue since it sometimes does it on the highway as well.

The engine sounds nice, the transmission shifts very smoothly. The Durango has ~114000 miles on it also.

 

this is usually caused by a bad TPS (throttle position sensor)

 

May also be a vacuum leak. Check all hoses for cracks especially around the ends and I’d probably go ahead and pop in a new pcv since there so cheap.

 

Alright, thanks for the quick responce guys.

One more thing I'd like to mention. While I was on lunch, I drove the Durango around for a bit. Around an hour later I'm on the highway and it seemed to start doing the issue I described about eariler. I come back to the office and put it into park...woah, RPMs go to ~1300 and just stay there. I give it gas for half a second and it dropped back down to ~600 RPMs.

I just wanted to add this little bit of information to help a little bit with troubleshooting.

Thanks.

 

Check your park/neutral switch... i had the same issue with mine.. after i replaced the TPS and the IAC it calmed down a bit but was still doing it... Turns out that the wires to the P/N switch had mated with the trans and where toasted! leaving it unable to tell the PCM what gear it was in and where to put the RPMs.. Switch cost me about $20 but i had to comb the boneyard to find a new plug as the dodge dealer wanted $50 for one...

 

Again, replace the TPS and take off the Throttle Body and clean it out really good including the IAC valve. It takes about 2 cans of Throttle Body cleaner and an old tooth brush. Don't push the IAC plunger in while cleaning. Then put it back to gether and reset the PCM:

 

Bought a new TPS and fixed it. Idels just perfect and runs smoothly on the highway .

$37 with a lifetime warrenty...sounded pretty good to me.

 

Remember to reset the PCM.


Glad you got it fixed!

 

Mine had an issue where it would move between about 600-1000 RPM while it was idling, then my check engine light came on eventually, turns out it was a bad power steering pressure switch. I guess the 4.7 had it, just to keep it from stalling when turning the wheel while the engine idles, if the pressure gets to high it revs the engine. After changing it, its idled perfectly.