Erratic RPM

I have a 2001 Dodge Durango SLT with the 4.7 liter engine. Recently, I've noticed an occasional behavior that probably signals trouble: erratic rpm with no change in footfeed. This usually happens between 600 and 1200 rpm, but I've seen it go as high as 2000 rpm. It sometimes happens at idle and it sometimes happens while I'm underway at low speed in 2wheel drive. It doesn't happen often, maybe once a week at this point in time.

Has anybody seen this before? Anybody know what it's telling me?

I had the same problem with my 2000 durango slt. I went to autozone and bought a throttle position sensor something like $25. Cleaned the throttle body where the throttle position sensor goes and also cleaned the throttle body where the Intake Air Control solenoid goes with carb cleaner and rags. Don't spray to much carb cleaner at once. Let it sit for a few minutes so carb cleaner evaporates.
Put in the new throttle position sensor and put the old Intake Air Control solenoid back in. Solved the problem for me.

Hope this helps! and Good luck!
Charm32