Low idle...stall...causing engine braking!!!

[35Remmy]

Hey guys...having a problem. '99 4.0. Start truck, engine idles down to 1-300 RPM and stalls, usually 2-3 times before it starts and holds an idle, but low...around 400. After that, it will start but idle at that low 400RPM.

While I'm driving, and I let off the gas, the truck will idle down by itself, literally engine braking. Say I'm at 2,000 RPM...I let off the gas, the idle will kick down to say 1,400RPM. Feels like I'm slightly applying the brakes.

I immediately thought throttle position sensor, so I changed it and no difference. Any ideas? Thanks in advance!!! .

 

[spraymonkey]

not sure about the newer trucks but i know when my IAC went to hell it idle'd pretty darn low after i cleaned it it ran pretty good for about a day or two then it was back at it so i just went out and bought another one.