As a follow-up on my problem with cold starts, I replaced the IAC yesterday. Van now starts right up, no idle issues at all. True test will be in a few days when the next weather front comes through late Saturday and temps will again be well below freezing at night.

Thanks to everyone for the information. My only problem was locating the IAC!! Once located by removing the doghouse, it was a 5 minute replacement time. Part cost was about $53 at Checkers. Ford dealer wanted $140 ! I didn't try cleaning as I wanted the reliability assurance I expect with a new part vs. cleaning/repairing the old.

 

Does any one have any ideas as to what else might cause this other than the IAC? I replaced it cleaned the MAF and got a whole tune up done and it still has this problem. Not as bad, it will just die once then start right up. Any ideas?

 

check the vacuum pressure....should be near 20PSI and steady.
recheck the vacuum lines carefully...& molded elbow on the PVC line near the IAC and PVC and lines associated with it.....then check the 2 smaller lines that come off the Drivers side exhaust manifold, these are a special silicon (ford only item) & 2 different sizes and will deteriorate, they go to the DPFE sensor/module.

If that it all good then test fuel pressure. see if it bleeds off pressure after it sits

 

enriched thanks so much for the reply! how do i check the vacuum pressure? when checking the lines and everything what should I look for?

Thanks so much

 

Matt, your welcome!
there should be a map of the vacuum lines under the hood, A sticker, near the radiator cover, or possibly on the under side of the hood. It shows where all the vacuum lines go. It'll give you a idea where they are within the engine bay.


With engine running you can wiggle/flex each of these lines & connections and listen for a hissing to increase & decrease as you flex the line and or connector. With increase of Hissing the engine prolly will stumble a bit or maybe change RPM. this is where the leak would be and needs to be corrected. Either replace the line or the connector. Over time these molded plastic lines get brittle and get hairline cracks or the rubber connectors/elbow deteriorate and leak

A quick way is to take a can of carb cleaner and spray down the vacuum lines as the engine runs. ( in your case on a cold start) and listen carefully for change in RPM, usually a increase of just a few hundred, (200-500 for example).

To check vacuum pressure, 1st you'll need a vacuum gauge ( sorry it maybe obvious to some, but not to all), then simply plug or T it into the line and take a reading as it is running, preferably fully warm. It can tell you a lot TRS Magazine - Dealing with engine vacuum

Considering that your issue is just on cold starts....it maybe wise to check the fuel pressure as well. You may have a weeping injector or a bad Fuel Pressure Regulator (FPR)