Engine trouble...

silverstang2001 · 02-23-2006, 12:04 PM

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

sacstoy02gt · 02-23-2006, 12:15 PM

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

silverstang2001 · 02-23-2006, 12:28 PM

Ok, I'll check it out. Thanks.

caballo · 02-23-2006, 12:32 PM

Here:

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

silverstang2001 · 02-23-2006, 03:06 PM

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?

NoKturnaL · 02-24-2006, 11:02 AM

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

cobra1923 · 02-24-2006, 11:32 AM

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

caballo · 02-24-2006, 11:39 AM

Quote:

Originally Posted by silverstang2001

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?

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

Isn't what bad for the gears/transmission?

caballo · 02-24-2006, 11:40 AM

Quote:

Originally Posted by cobra1923

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

PCV is on the passenger side valve cover.

silverstang2001 · 02-24-2006, 01:23 PM

Quote:

Originally Posted by caballo

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

Isn't what bad for the gears/transmission?

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

caballo · 02-25-2006, 01:52 AM

Quote:

Originally Posted by silverstang2001

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.

Joel5.0 · 02-25-2006, 06:11 AM

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 miles per hour 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.

02-23-2006, 12:04 PM	#1 (permalink)
silverstang2001 Damn Hippies!!! Join Date: Jan 2006 Location: Chico, CA Posts: 306	Engine trouble... 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

02-23-2006, 12:15 PM	#2 (permalink)
sacstoy02gt Senior Member Join Date: May 2005 Location: Wind Lake, WI Posts: 147	IAC - probably gummed up or shot. Clean it and see if it helps, if not, buy a new one. __________________ Satin Silver '02 GT - Just a little twin-screwed 4.6...

02-23-2006, 12:32 PM	#4 (permalink)
caballo Exceptional Member Join Date: May 2005 Location: NE CO Posts: 530	Here: http://forums.stangnet.com/showpost....50&postcount=1 __________________ My eyes!!! I can't see my eyes!!!

02-24-2006, 11:02 AM	#6 (permalink)
NoKturnaL MustangTuning 5-oh Join Date: Dec 2004 Location: Peabody, MA Posts: 1,950	which one is the IAC and the PCV valves? pic? __________________ 2002 Mustang GT Coupe 5-Speed Performance K&N Intake Accufab upper Intake Plenum Accufab 70mm Throttle Body Steeda Pullies SCT 4-Bank Chip Dyno Tuned Mac H-pipe Flowmaster Cat-Back Steeda Shifter Centerforce Clutch SLP-Line-Lock And more upgrades visually

02-24-2006, 11:32 AM	#7 (permalink)
cobra1923 Senior Member Join Date: Nov 2004 Location: Baltimore Posts: 584	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 __________________ 2003 10th Anniversary Cobra Convertible All Stock and staying that way... well maybe some pipes since it's so quiet..ahhhh! it's a sickness 1995 mustang GT vert - all black (almost back together)

02-23-2006, 12:28 PM	#3 (permalink)
silverstang2001 Damn Hippies!!! Join Date: Jan 2006 Location: Chico, CA Posts: 306	Ok, I'll check it out. Thanks.

02-23-2006, 03:06 PM	#5 (permalink)
silverstang2001 Damn Hippies!!! Join Date: Jan 2006 Location: Chico, CA Posts: 306	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?

02-25-2006, 06:11 AM	#12 (permalink)
Joel5.0 Junior Member Join Date: Oct 2005 Location: Puerto Rico Posts: 22	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 miles per hour 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. __________________ ACRONYMS: LUK=Let Us Know, GL=Good Luck, LMK=Let Me Know, JIC=Just In Case, BTSTDTRT=Been There Seen That Done That Repaired That and the classic... DILLIGAS=Do I Look Like I Give A S*** 1986 Mustang GT Hatchback w/T-Tops :wallbash: NOW: 5.0L Stock, 289 '66 Heads, 700CFM Holley DP, X303 Cam, 1.73 RR's, R. Gear 4+1 Tranny, 2.73 Gears. WIP: 3.90 gears, Granatelli New Design Adjustable LCA's and UCA's, T-Top weatherstrip kit :censored:

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