Idle Air controller

I have a 1996 ford windstar that runs terrible. The engine shakes and rattles. It started about 4 weeks ago. When I disconect the IAC it gets better, but even with a new IAC the problem persists. What can I do?

Are you sure it is a new IAC? I find it hard to believe, but there is an outside chance that the IAC is clogged. A good spray down with throttle body cleaner should help the issue if that is the case. I am willing to bet though, that if you know how to disconnect the IAC, you have already tried this. Is this the case? I am almost willing to bet then that the hose coming off the IAC is bad.


Thanks, I’ll give it try.

“I am almost willing to bet then that the hose coming off the IAC is bad.”

What hose?


Sorry, should have been a lot more specific. There are probably three hoses connecting to the IAC. The outer two are probably coolant hoses (water bypass hoses). The middle hose (or whichever hose you see running to the engine/intake manifold) is the one you want. It is called the air assist hose. Also, don’t flood your IAC valve with solvent unless you can identify the hose I am talking about. (If you flood it with solvent, you just pull the hose and the solvent with the dissolved crud will flow right on out).


There are no hoses going to the Idle Air Control valve. This is a stepper motor mounted on the throttle body with just a single electrical connector plugged in. See any hose connections?


Didn’t check the parts. I have three hoses on my IAC. Still wouldn’t hurt to try to clean it out, especially if it’s not new and to clean the electrical connections.

When you disconnected the IAC it maybe put the engine computer in a “limp home” mode, disabling the problem maker.
My guess is the EGR system

I’m in agreement with tester, I’ve never seen an IAC with anything except for the one connector. I think you are confusing the throttle body with the IAC.

Some IACs, like the ones on the mid 90’s 4.6L engines do have an air hose connected. Others, like this one, don’t. I have never seen any that had coolant hose connections (plenty of throttle bodies do).