Ford Repair: 98 ford explorer hard start, upper intake manifold, air control valve

Question
My 6 cyl 98 ford exp (sport) doesn't keep an idle in wet weather.  I noticed it first this summer.  I have been able to get to to start by applying gas.  Then after I'd say 60 sec or so it will keep an idle.  Before that though if I do not keep feeding it gas it stalls.  This morning however the problem has climaxed.  I washed the car yesterday and today it is cold and wet out (a little snowy).  My mechanic said something about air intake.  Any suggestions?

Answer
Intermittent hard starting is a commom problem with Explorers. The most common cause is a bad Idle Air Control Valve (IAC).  When starting the engine and at idle, the throttle plate is closed and the only air entering the engine is through the IAC.  This is all controlled by the Powertrain Contol Module. It uses the IAC to allow a small amount of air to enter the engine for starting and to adjust idle speed. The IAC is mounted to the upper intake manifold with two small bolts, and has a small electrical connector on it. It is about two by four inches. It may be sticking closed in damp weather.  You can remove it (be careful, it may have a paper gasket) and clean it out with an Air Intake Cleaner. If this doesn't help, it may have failed and need replacing.

I hope this helps,
Dave