While driving, when I put the clutch in and/or shift to neutral the RPMs do not fall to idle. Can anyone tell me what this might be? :helpsmili

 

IAC - probably gummed up or shot. Clean it and see if it helps, if not, buy a new one.

 

Ok, I'll check it out. Thanks.

 

Here:

http://forums.stangnet.com/showpost....50&postcount=1

 

Thanks for the info, Caballo. But, the article makes it sound like this happens to all Mustangs and that Ford has designed this to happen normally - I honestly don't remember this happening when I first bought the car, and it seems to be getting worse. Also, isn't it bad for the gears/transmission?

 

which one is the IAC and the PCV valves? pic?

 

IAC has electric wires hooked to it and it's on the front of the throttle body.. PCV has a 3/4 inch vacuum line hooked to it with no electric wires. I honestly forget right now where the PCV is located.... it's either somewhere in the manifold or on a valve cover.. Someone will remember specifically

 

It doesn't happen to all mustangs, just some from what I've heard.

Isn't what bad for the gears/transmission?

 

PCV is on the passenger side valve cover.

 

Switching gears while the car is running between 2500 and 3500 rpms? It seems like it would add unneeded wear to the tranny or clutch

 

Eventually, I'm sure it would, but that's why you do the fix. This is something that has been going on with some of the mustangs at least since 99. It's not really that huge of an issue that would cause drivability concerns. It's more of an annoyance. You are never shifting at idle anyways unless your shifting from a stop.

 

The "hanging" idle while shifting is programmed into the ECM. Anytime the ECM sees an input from the VSS, the system assumes the car is between shifts and the IAC frequency is kept high.

You can check if it's really a problem by watching how the RPM control back to idle does while the car is sitting still, and the difference once you have the car moving (anything over 1 MPH from the VSS will do it)....this is normal,....annoying, but normal. The posted fix should help in reducing the annoyance factor, w/out causing any codes to show up. Keeping it the way it is shouldn't cause any additional wear on the clutch or tranny components.