High idle question

I ran into a problem at Moab. When I first started my rig, it would idle at 2-3,000 rpms for 10 to 15 seconds, then it would drop to normal. It did it for several days. Now I'm back home, it isn't doing it anymore.

I've seen this talked about, but can't find the thread. What did you guys track it down to?

I guess I better add this since I'm always hassling people for not including it. I'm running a 4.7l Stroker w/renix and AW4.

Mine was doing the same thing, was having fits trying to figure out what was going on. After tearing down the TB, cleaning the IAC, adjusting the TPS and checking all of my vacuum lines, grease on everything and everywhere, my daughter comes out (clean, scrubbed, cute and smelling good) mentioned it only happened when the heater was on. :doh: Small vacuum leak in the heater controls, think it´s the defrost door diaphram. Seems to be most of it, but not all, it´s gotten better, but not cured, like a 90% improvement. Try switching the heater (HVAC controls) to off, before stopping the motor and see what happens
Just guessing, but thinking, sometimes the vacuum canister may leak down, which adds to the problem. At least in mine. Suspect maybe a surge of air into the intake, as the canister is vacuumed down. Pretty sure the canister is supposed to hold vacuum.
Suspect a check valve for the heater vacuum controls (or another) is also sometimes sticking, allows the canister to bleed down, through the heater controls (or someplace else). Still a work in progress, but most of it seems to be a vacuum leak in the HVAC controls/system.

The IAC on RENIX have a tendancy to carbon up the pintal in/out thread. You might try removing the IAC and spraying carb cleaner in the thread behind the pintal. Let it drain and dry and put a little "Break Free" on the threads. If it still revs, check the ground path of the TPS through the c101 connector.

I got rid of the C101 connector when I did the wiring for the stroker. I didn't think it would be the IAC because it does end up adjusting , but I will give it the once over anyway.

Thanks