Good morning.There are a couple of things I would do.First check the throttle bore and make sure that it is clean.If it is carboned up(black stuff) it can cause the type of problem you are having.If it is dirty, cleanm it with some throttle body cleaner(available at any parts house).When you clean the throttle bore wet a clean cloth with the cleaner and wipe the surface especially where the throttle plate rest.Next it would try another IAC motor.I know you just got one but I had a problem with those in the past.I went through three motors before I got a good one Talk about drive you nuts.I would also recheck for any vacuum leaks using the throttle body cleaner.Just spray around the engine along the intake manifold and the vacuum hoses.If you notice the idle change at any point look there for a vacuum leak.Ford had a problem with some of the hoses where they bend(90 degrees) but the "hole" would be on the underside and you could not "see" it.Please let me know if you need more assistance,Don P.S. Have a Happy 4th..
I will try the Throtle body cleaning, I remember having issues with my 88 Town Car 5.0, and That taking care of it. With the IAC, It doesn't appear to be "Sticking", because when I disconect the MAP, it drops down, which leads me to think, the IAC is being held open electricaly???
Hello Donald, Well, Tried the throttle cleaning, and check for vacuum leaks, all with no success. Pulled the IAC back off, and cleaned and reinstalled the original... GRRRRRRRR the car is running smoothly. I have had luck with such parts from the Advanced store, but will have to see how they feel about taking this one back, or replacing "IF" they have one... I think if they don't have one. I might steer my friend to either a NAPA, or Ford Dealer.
Thanks again Lonnie