My 2001 4.7 with the 5sp 'lopes' at idle sometimes. By lopes, I mean the idle speed increases and decreases from 500 to 1100 RPM. Not always, and it usually is occurring when the engine is fully warm and the AC is operating. No codes and other wise runs great.

 

IAC valve or TPS. Replace only with mopar. Check plugs too.

 

In addition to the above, when did you last clean the throttle body - as in remove it to clean it?

Mine occasionally does the same thing, 4.7 5 speed.

 

The throttle body has never been cleaned nor removed.

 

It wouldn't hurt to clean it out then. You'll be surprised at the amount of crud that collects.

 

I have just purchased a 2005 Dakota 4.7L. This idle surge from 500-1200 rpm is the very first problem. (only had it a week). I have been searching and this seems to be the answer.

 

Vacuum leak?

 

No the throttle body cleaning and the TPS.
Its always good to check vac lines.