My truck ('04 2.3L, 5 spd) has been having an intermittent problem with idling. No check engine light. It normally starts and idles just fine, but sometimes will start and sputter around 500 rpm, almost dying, and will continue to do so until I push the gas to the floor. Once it revs up it will come back down and idle just fine. I immediately assumed that it was the IAC so I replaced it but it is still doing the same thing. I have been looking for any kind of pattern and I noticed that it does it more often when I drive the truck a short distance, shut it off for less than 2 hours or so, and then try to start it again. I cleaned the MAF sensor with MAF cleaner and there is no change. I figured the MAF sensor malfunctioning would throw a code anyway but I didn't know what else to try. Any help would be great. Thanks.

 

This may be a separate issue or maybe part of the same issue but I am also hearing what sounds like a faint exhaust leak. The reason I am not flat out calling it an exhaust leak is that you cannot hear it while the truck is idling and doesn't get louder when the truck is under load (like going up a hill). It mostly happens when coasting to a stop sign or maintaining a constant speed on the highway. This started around the same time as the idle issue. Any ideas?

 

Try some Lucas Fuel Treatment.
Lucas Fuel Treatment : Lucas Oil

 

Was wondering if you ever fixed this?

I have the same truck as you and have been having the same problem for about a year now. I've just gotten into the habit of tapping the gas when I start it. Last time I had it in the shop for the slave cylinder they said it might be a leaky injector. It has never stalled when driving so I haven't been in a hurry to fix it. Would make it harder to steal as well, I guess.