540im won't idle down!!!! PLEASE HELP!!!

[JKBe30m3]

I have been going around in circles with this car for months. I have replaced the ECU, throttle position sensor, Idle control motor, and maf. I am out of ideas! Can an intake leak cause this problem. THe car will rev when you give it gas but it won't come down. It will idle fine but once you give it gas it won't settle down. If I unplug the Idle control motor the idle goes to normal and it revs down but the check engine light comes on and it does run just right. I have replaced the sensor so I know it isn't that. Any ideas would be greatly appreciated.


Thanks

Justin

[JKBe30m3]

I have also replaced the wiring harness

[GJPinAU]

Have you checked the actual throttle cable?
Mine had the same problem after some work was done under the cover and I discovered the plastic screw-in adjuster had broken and was jamming the cable enough to keep the idle high.

[JKBe30m3]

I have found that if I unplug the ICV the car runs, drives, idles fine. WHen I plug it in the car revs up to whatever rpm you rev it to and it stays there. I don;t know what else it could be. I have replaced the idle control valve to no avail.

[JKBe30m3]

bump

[BillionPa]

Maf?

[BillionPa]

actually, the ICV is closed without voltage. the fact that the car still idles with it unplugged means you have a massive vacuum leak!!!

[632 Regal]

there are 2 identical connectors that are interchangable in that area, it may be possible that you have them switched causing this problem. Sounds silly but when I pulled my intake it took a while to figure what went where.

[Tiger]

Floor mat! Really. I once had this problem...and the answer is the floor mat is holding the throttle pedal down.

[Tiger]

Another possibility is leaky intake manifold... or loose vacuum hose... both will cause high RPM regardless of anything else.

[JKBe30m3]

I took the floormat out to eliminate that from the equation. I have had the car's intake manifold smoked (using a smoker or fog machine designed to find vacuum leaks in automotive applications) and I have found no problem. If there was an intake leak the car wouldn't idle fine with the idle control motor unplugged. Any other ideas?

[BillionPa]

if the leak was constant it would, such as the charcoal canistor purge valve being stuck open.