idle high and doesn't drop when letting off the gas

[mcluga]

I have a 2000 Taurus and just a few days ago, it wouldn't idle at all. Whenever you let off the gas pedal, it would immediately die.. even when driving down the road. I took off the Idle Air Control Valve and the problem was fixed. BUT, now when you are driving down the road and let off the gas pedal, the rpm's don't drop and if you put the car into neutral while driving, the rpm's actually climb up without ever dropping back off.. about 500 rpm increase. It feels the car is trying to go when you let off the gas and apply brakes... increasing braking distance and the gas mileage is noticeably worse than it used to be. How do I fix this High Idle problem?? I completely replaced the old idle air control valve with a new one, but it didn't fix the problem.

[far far away]

Originally Posted by mcluga

I have a 2000 Taurus and just a few days ago, it wouldn't idle at all. Whenever you let off the gas pedal, it would immediately die.. even when driving down the road. I took off the Idle Air Control Valve and the problem was fixed. BUT, now when you are driving down the road and let off the gas pedal, the rpm's don't drop and if you put the car into neutral while driving, the rpm's actually climb up without ever dropping back off.. about 500 rpm increase. It feels the car is trying to go when you let off the gas and apply brakes... increasing braking distance and the gas mileage is noticeably worse than it used to be. How do I fix this High Idle problem?? I completely replaced the old idle air control valve with a new one, but it didn't fix the problem.

Hi,

I've a 2001 Taurus with exactly the same issue. I have the car since 2003, it always had this high idling when driving (almost no engine brake power). Other than that, no apparent issues, Mileage is OK (20-24 MPG) but it always annoyed me (and I guess I'm not getting the best gas mileage possible)
How did you resolve the issue of high idling when you let off the gas? Also when driving and when I put in neutral, the RPM's go up just as you describe.
Thanks

[BroncoJoe19]

High idle is often caused by a vacuum leak, do you know how to check for a vacuum leak?

[khooper]

This is almost always caused by the Idle Control Valve (IAC), which is located near the firewall, on the passenger side, next to the throttle body.The high idle in drive and park is tough on the engine and murder (in drive) on the already fragile transmission, not to mention the brutal effect it has on U-joints when you shift into drive at high RPM's, so you want to get it fixed as soon as possible or park it until you can solve it.
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ford f150 parts

[jfjohn]

It probably is a vacuum leak but aren't you supposed to reset the computer after changing any parts?

[admnt186]

To check for a vacuum leak, go to your local parts store and get some carb cleaner (B-12) spray. Be sure to have a fire extinguisher ready whenever doing these kinds of tests. Start the car up and let it run for a bit. Very lightly spray the area where you think the vacuum leak is. If there's a leak, it will suck up the B-12 and the engine will rev up and you've found your problem. Simply replace or refit the part or hose and that should fix it. In the case of the Taurus, there is actually a problem with the PCV valve and the gaskets on the intake. The ones on there now should be black. Those apparently are easily worn and can become brittle or cracked easily causing the vacuum leak. The new ones are green. You can get those at your local parts store. I believe another car forum has the list of parts required as a sticky because it's a common problem with models later than 2001 when they updated the parts. I will try to get my hands on that list and post it here shortly.