Drives itself up to 20mph until warm

I have a 2003 windstar with 40K miles, and has no error codes... on cold start, i can drive it the first ten minutes without giving it gas, it can get to 20mph on its own, then once reaches operating temperature, its fine somewhat, and the rpms get down most of the time, but still seem high at 850-900. I tried cleaning the IAC valve and throttle body, and its still doing this, and its driving me nuts. I noticed that the IAC valve when I removed it is not fully seated or closed, instead its slightly open. Is it supposed to be fully closed when no voltage going to it ? Maybe this is the problem.

I was told to check vacuum lines, I will do that tonight the best I can. One thing I did notice, and I don't know if normal or not, but the PCV valve's rubber connector sheathing where it connects to crankcase, the rubber is two pieces, I'm not sure if its supposed to be one or two. Could that be a vaccum leak ?

And does anyone know if these isolator bolt leak issues affected the 2003s?

I will be ultra grateful for anyone who can help me solve this problem. THANK YOU IN ADVANCE

And does anyone know if these isolator bolt leak issues affected the 2003s?



I can attest to the 171/174 problem affecting a 2003. I have a 2003LX and I had to do the repair about 2 months ago. I also recently had an high idle problem but spraying some wd-40 on the throttle area seems to have cleared it up.

mundy5,
did you get those 171/174 codes? because i'm not.
how was the car behaving before the fix ?
this is driving me nuts.

The IAC should be closed when no voltage is applied, so if you remove it and it is not totally closed you should see or clean the little shaft that is possibly dirty. The IAC will open when you start the engine and produce a fast idle condition which close quickly after starting and engine run normally. If it does not close after starting the fast idle will continue and this is possibly what happen now.

Other possibilities are a "quick" thermostat ... or a "slow" ECT sensor.

diclemeg,

My windstar behaved perfectly before and after the 171/174 fix. I only did the fix b/c of my cel. My high idle began during and after my transmission fluid flush. I doubt the two issues, high idle and the transmission flush are related at all. I did not do anything with the IAC. The high idle has not returned for 2 weeks now since it began exhibiting the high idle.

just to be clear on the IAC... when i took it out to clean it, it was a little dirty but not much. but, i noticed that the cone was not completely seated in its seat, rather, was open by about 1/8 inch i think. i went to autozone to compare a new one but a different model, and it was similar, also not fully seated.

i heard that maybe, its my MAF sensor.... but i dont understand why im not getting any codes !