First post here, hoping to gain some knowledge. I have a 2003 Durango slt 4.7 , its idling high after warming and going in to closed loop. I have replaced all bad vac lines, tps, cleaned iac and throttle body. When cold it idles around 1000 in park then once it goes closed loop it shoots up to about 1200 in park and 1000 in gear, also when i let off the gas at pretty much any speed the rpms will jump around by about 300-500 the car does accelerate on its own when doing this. I originally was going to replace the iac but wouldnt the iac affect it closed and open loop? any suggestions?

 

i would lean towards the IAC, 1000 rpm idle is high no matter which loop the engine is running under, mine idles around 800 when i first start it in the morning most of the time, even in the 0-10F days last week it settle below 1000 rpm in just a minute or so.

IAC, TPS would be my first thoughts, ill try and find my research on which sensors are monitored at idle to give you a full list to check when i get home from work tonight

EDIT: the only sensors monitored in closed loop that are not monitored in open loop are the oxygen sensors

 

Update....new iac , tps, o2 sensors, claned throttle body, no more fluctuation but idle still goez to about 1300 rpms in park once it goes in to closed loop...have used several cans of carb cleaner looking for leaks but still found nothing. Pulled brake booster line and plugged hose to see if idle would go down and it stays the same...only sensors I have not replaced are the coolant temp sensor and the map.....baffled here any suggestions?