As the title states i have sorta a rough idle not as much or should i say nearly nothing while in park... once placed in gear it sorta idles roughly and while in gear when i let off the brake my durango kinda jerks/ slight jumping/ has like a bouncy idle its hard to explain exaclty but you get the idea, very hard to pinpoint an exact issues because i couldnt fins similar problems while searching. Ive read things about the iac and tps but im not sure if those could cause an issue. Other than that the 4.7 runs very very well and is strong. Spark plugs have been recently changed not too long ago. I did recently have the #6 coil go bad changed it and light has been gone but im not sure what the issue could be i also tried seafoam.

 

I have the same engine in an '02. I replaced the TPS in December. First thing first is just double check the vacuum hoses for cracks, but I don't think that's it. I would put my money on those two culprits.

The TPS will make the RPMs bounce up and down as it tries to rectify poor resistance in the sensor. The last straw for me was that it started kicking and jumping hard going down the highway in Cruise control.

The IAC - if that is your problem will move much slower. If that is worn or clogged with carbon, it can't open all the way and your engine suffocates when idling. Then you hit the throttle and the engine gets it's air - suddenly the IAC can't close fast enough and it's getting too much air and causes your jump.

Cheapest option (but time consuming) is to just pull apart the throttle body, clean it and the IAC with carb cleaner and re-assemble. DON'T get Carb cleaner in the electrical end of the IAC! Next cheapest is to swap the TPS. Quick and easy, and under $35. Most expensive (but still quick) is to replace the IAC.

The last couple weeks I've noticed that my idle RPMs are slowly dropping. Still steady, but down to 500 RPM, so I'm going to do that very cleaning once I get a nice warm Saturday.

Good luck