IAC Valve

[Estima]

Hello All, I Have a 2004 Montaineer with the 4.6 V8, would a bad IAC Valve cause stumbling in the engine during idle? Hard Starts once in a while or in other words longer crankig to start it? and also a random misfire in cylinders 4 and 7? that's the code that advance auto parts pulled. My Check Engine Light comes on one week then gone for three days or so then back again. Forgot to add I have 68,000 miles and the plugs and coils have never been changed.

 

[E.B. Cornburner]

Change the plugs. If that doesn't take care of it, then it might be a bad coil. Rule out the cheapest stuff first.

Your '04 doesn't have an IAC valve. The electronic throttle body just positions the throttle blade to give you the correct idle speed. It might be worthwhile to clean out the throttle body...Take some carburetor or air intake cleaner and clean both sides of the throttle bore and blade.

 

[Estima]

OK I will try changing the plugs this weekend, thought all had the IAC Valve thanks.

 

[E.B. Cornburner]

I did too. It wasn't till I started to get more familiar with this electronic throttle body that I realized it's no longer needed. Neither is the cruise control servo needed anymore. None of that really dawned on me till I was detailing the engine bay one day and realized they weren't there.

 

[Estima]

I took a gamble on changing the coils, #4 and #7 and boy what a difference the truck really takes off now and Idles smooth, and also cleaned the throttle body. I was going to try to reset the check engine light, but it went off by itself after about 15 minutes of idling. Thank You for the Advice.