I have a 1998 Dodge Ram with a 318 in it, and today it started stalling or the rpms would get pretty low when i start slowing down, then it goes back to normal. When i rev and hold to about 2000 rpms and let off it dies, but if i rev to about 3000 rpm it idles normal. I cant seem to find anything by visual inspection other than the air filter needs replaced. Also idle air control has been replaced about 2 years ago.

 

Has the plenum been fixed?

Wouldn't hurt to pull the throttle body, remove the IAC, and clean it, and it's bore REALLY well. Leave the battery disconnected while you are playing with that.... when you have it all back together, turn the ignition to "on", (don't touch anything else,) count to ten, THEN fire the engine. Let it relearn idle.

If that doesn't help, might be time to replace your IAC. Again. What brand did you get the last time? I know my truck really didn't care for the aftermarket IAC I tried to use. Put in a mopar part, and all was well again.

 

This morning I pulled the IAC and cleaned it, I relearned idle and it seemed to help. Now it doesn't stall but it still has the lowering of rpms when I let off the accelerator pedal, I ordered an IAC from the local Dodge dealership, hopefully that helps. I also replaced the air filter.

I don't know what brand of IAC they put in it, but I think it is one from NAPA.

 

Let us know what happens with the dealer IAC. That *should* solve the issue.

 

New IAC is in, seems to run fine now. Still has a slight drop in rpm but nothing as drastic as it was. Test drive was fine, drove well.

Also I compared the new IAC with the old one, there wasn't any noticeable differences. Except that on the new one has some numbers on the back of it by the connector, the old one looked like the numbers were ground off.