60valves

I did search, yes.
'02 Ram 2500. Recently started getting an intermittent rough idle. The truck idles normally, but will drop 50 rpm. It sounds very much like it's on 3 cylinder idle, or that it is starving for fuel, which it isn't. The fuel pressure will INCREASE when this happens. The engine can be rev'd out of this and will return to normal idle again. This only happens in off-throttle situations ie; idling or deceleration. I have replaced the IAT and the APPS, same problem persists. Also have verified that there are no air bubbles coming from the coolant to try to rule out the head gasket. My next thoughts are cam/crank sensor, injectors or ultimately, the ECM(hope not).

Any thoughts?
Thanks for your time all.

SIXSLUG

That is odd. The 3 cylinder hi idle needs a few parameters met to kick in and it sounds like you have covered them all.

IIRC it can be activated with the cruise switch, maybe clockspring going bad?

Just a thought of something you may not have checked.....

60valves

I haven't checked that but will definitely look into it now.
Thank you.

cougar

What do you have for a lift pump and what are your fuel pressure readings? You may be sucking air into the fuel.

60valves

Running an AirDog 165 pulling fuel from a sump. Fuel pressure is always between 18-21psi.

SIXSLUG

Cougar may be onto something....

60valves

Hoping to have this issue fixed. It was looking like an injector was occasionally sticking closed and causing the problem.

I bought a gallon of Power Service Arctic Formula. Dumped the whole bottle in the empty tank and drove like an a$$ho!e to the fuel station to fill up.

That was 3 days ago and, knock on wood, there hasn't been an issue since.

Thanks for your help guys.