Engine Lope at Idle.....Sometimes :(

[fenex]

My 06 Ram 2500 CTD will occasionally begin to lope if I sit at idle with the engine in park, the problem seems to occur more frequently when the engine is warm. The truck has 220,000 miles on the original injectors, it runs well and always starts without issue. I have notice that when the loping begins, I can turn on the AC or gently increase the RPM and the issue goes away and the truck begins to idle normally for a few minutes before it begins to lope again. I am the original owner and have always replaced the fuel filter at every oil change ( 5k miles ) and run injector cleaner thru the system about every other fill up, I replaced the FCA last month.

Any thoughts ??

Regards