I am haveing the same problem did you get the idle prob fixed.If so what did you do.

 

Trailman, The problem I had with my truck was a bad intake manifold gasket. My truck wouldn't idle less than 1500RPM's. I sprayed carb cleaner all the way around the base of the manifold until the idle changed. It ended up being underneath the plenum. I'm not sure if you followed the rest of the thread or not, but the sticking IACV could be a problem, and it's fairly easy to clean.

 

I was having this same problem, I decided just to replace the IACvalve and the truck runs great, even in the cold weather we have been having. Truck would never hold Idle when it was cold outside, and when it did it Idled really really rough. I would strongly suggest you just replace the IACvalve. Its a long shot but your T.P.S. (Throttle Position Sensor) sensor may also need replaced if your having lunging problems.

 

Thanks guys, I still haven't fixed it yet. I'm going to replaced the iac first, then it still happens replace the tps. I don't drive the truck much, maybe 3,000 miles a year. So i just haven't fixed it yet.

 

Hi Triplepower, I have a 91 F250 with a 351, mine idled like it had a big raceing cam, up and down if you know what I mean, the MAP sensor went bad I unpluged it while it was running and it smoothed out. The codes had me replace " IAC,TPS, plugs, wires, O2 sensor, nothing helped. I was trying anything when I pulled the wires off the MAP sensor, $48 later it runs like new. It don't cost to pull the wires, try it, I didn't even know what it was till I got to the parts store and told them, here this is what I need!

 

Where can I find the map sensor, and where is the plug to unplug it. That might be the whole problem?

 

The MAP sensor is on the fire wall by the ac unit, right buy the motor. Just unplug the wires, there is a vacuume hose also, but unplugging the hose made no change. It's a black box about 3"x3" buy inch and a half thick.

 

I just replaced my map sensor and it didn't change the idle.Well it was worth a try,next is IAC I cleaned it out but it might just be no good.
I am not trying to hi jack this thread,triplepower is just having the exact same
problem that i do..