Idle Air Control question...

Do you actually need the IAC... can you keep it unplugged?

The IAC is pretty important during cold starting. On my 88, the IAC failed partially open so my idle was near 2000 RPMs so I made a plate out of aluminum with holes drilled in it to allow air to enter through the IAC and into the engine at a predetermined amount. Worked fine for me, but I only drove the car to and from work which was a few miles. I was selling the car and didnt want to spend the 60 dollars on a new one. This was before I started my second job too. I would definitely get a new IAC if this is your daily driver or even something you drive on a regular occasion. Definitely go Motorcraft.

I had this same problem on my '89 GT 5.0 did the usual clean throttle body and IAC, ect.. eventualy I started back at the basics and concidered what would really be the simplest solustion and started to look for cracks in my vacuum lines of course I eventually found it and problem solved $0 spent. I know if it went into a shop they would have gouged me for big $ and alot of unneeded parts. Skip to last week now my 2002 GT is rough idling and high idling when I let off the gas for about 15 secs (while I'm moving at any speed). Now my 1st plan of action was to read scan codes witch was my 1st mistake it pointed me to a lean system and bad O2's. But if you look at FORDs tech sheets on how the OBD II flow chart works, it will skip some tests if components before that test have failed or didn't respond. So more than likely you get incorrect readings. So I read the forums and saw that everyone jumped on the IAC and O2 replacement bandwagon with poor results. So for me it was back to my original plan of simple but most important vacuum leaks and I came across a tech sheet that was not aimed at my car but had a truth to it for all cars, it suggested to hose clamp on the pcv valve connections on all connections, I was in the process of this and found my large hose from passenger side pcv to TB was cracked along the bottom. After replacing it and clamping all other hoses my car purrs at 550 rpm (automatic trans) improved 2nd gear slam and all around drivability. So first check fuses then vacuum for any engine rough running condition they cost you nothing.

just noticed that my stang has the same problem. Idling @ 1200rpms... where do you guys normally order you motorcraft parts from? rockauto has it for $115. any suggestions on where to get it cheaper?

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reset my idle per R.J's walkthrough the other day.
excellent write-up

Thanks, I'm glad I could help