changed air filter, now stalling surging at idle

Changed the air filter on a 2000 Windstar. Noticed a high idle after first start up, but then everything seemed fine after a test drive. Now stalling and surging whenever sitting at idle, almost like computer can't figure out what's going on for air/fuel mixture.

Any ideas? Thanks.
--jsfx3

Changed the air filter on a 2000 Windstar. Noticed a high idle after first start up, but then everything seemed fine after a test drive. Now stalling and surging whenever sitting at idle, almost like computer can't figure out what's going on for air/fuel mixture.

Any ideas? Thanks.
--jsfx3

Definitely check for air leaks, maybe the air filter canister didn't go back together right on the underside where it's not visible?

no idea how these things are related, but after listening to the engine closely, I found a cap covering a vacuum connection near the top centre of the engine in the area of the fuel rail.

replaced the cap, and everything is running fine.

What continues to be odd, is the cap occasionally coming loose / blowing off, but otherwise everything seems to be fine.

thanks
--jsfx3

I have this problem, and the little u shaped hose front center top of engine, connects near the fuel rail.

Could this loose hose be causing erratic idle while driving....

with the engine running is has good suction and stays in place, but with engine off, it is super loose

That's a vacuum port and is connected from the Intake manifold to the Fuel pressure regulator. If the hose comes loose you'll get idling problems because you have a vacuum leak and the Fuel pressure isn't being regulated anymore causing the fuel to starve.

Best regards,

Oscar.

Ford dealers get around $18 for that U shaped tube with the rubber boots.
They are known to come off. Take a plastic cable tie to clamp the ends.

...or go to eBay and search on "47096 Vacuum Hose" for the Dorman aftermarket replacement.

you know, i think that was my problem, but when you are driving wide open, it didn't seem to affect the engine running, only at stop lights, and parking lots, etc....

when I put on the new IAC, it didn't help, but the symptoms where similar.

Yes, small vacuum leaks don't tend to be noticeable at higher engine speeds. The quality and speed of the idle are very dependent on a vacuum system that's working correctly.