Bad Idle Trouble

Jeff7477 · 08-29-2001, 11:07 AM

I am having some problems with the way my car runs. When its cold, It will start, and idle good for a couple seconds, then hesitate and drop to under 500 rpms, then regain itself. It does this till its warm, and it stops. Also, Sometimes the car will idle above 1000 rpm until you stop and restart the engine. What going on?

Sneaky · 08-29-2001, 02:01 PM

What year Mustang do you own? If it is a 87-88 speed density I would check the idle air bypass valve. What mods do you have? Need more info.

95mustanggt · 08-29-2001, 02:40 PM

You're going to have to give a little more information on your car before anyone can give you some help.

------------------
1995 Mustang GT

posied88 · 08-29-2001, 03:46 PM

I have somewhat of the same problem. It idles around 1000 and then drops to about 500.It does almost anytime though. When I'm at a light I sometimes have to give it gas or else it will die. I dont know what it is but I recently installed an off-road H-pipe, and it never had that problem before. I thoght it was my cam at first because it did it before but very little like when it was hot or cold. I also thought it may be my timing.maybe someone out there can help me with a solution or something.
Thanks.

------------------
3.55 gears,posi,mac 1 5/8 shorties,off-road h-pipe,w/flowmasters,bbk 65mm throttle body,frpp aluminum driveshaft,frpp b303 cam,hurst short throw shifter.

Jeff7477 · 08-29-2001, 05:56 PM

Its a '90 and only things are headers, h-pipe, and cat-back

exgmguy · 08-29-2001, 08:31 PM

Clean the idle air motor, check the TPS, and reset the computer.

------------------
1988 Mustang GT
11.8 @ 123 (7/14/01)
1992 BadAzz Wrangler
1993 Explorer

See my car at: www.mustangworks.com/cgi-bin/moi-display.cgi?179

gofastmercury · 08-29-2001, 11:09 PM

When my 93 did that, I cleaned the throtle blade. It has a little hole in it, and if it plugs, the idle goes wonky.

------------------
93LX excopcar 150K 3.55's mac full headers. funnest car I ever had.
14.3@96 @ 4000ft
67 390 ranchero 3.70's cast manifolds, comp cams 260H, completly stock
15.1@90mph
66 merc comet 351w, isky roller 600 lift 268/260@.050, vic jr. 700DP, 5000stall, 4.56's c-4, 3400lbs with driver

posied88 · 08-30-2001, 12:22 AM

Thanks guys Ill look into those things.

HAITHAM · 09-04-2001, 06:48 AM

There are any improvement ?????

------------------
94 COBRA # 926/5009
TFS track heat heads (ported), Cobra intake (ported), 24# Injectors, 3/8" Phenolic spacer, E303 Cam, TFS 1.7 rr
BBK 1 5/8" headers, BBK 65mm TB, Pro-M 80mm MAS, PIH kit w/ A9L computer, FMS 3.55 ratio
BBK 190 lph fuel pump, Paxton fpr, MSD'S, March Pulley's, Pro-5 tower power shifter, Autometer shift light (5600),
Intellitronix Air/Fuel gauge, Eibach Sportline Springs, Tokico 5-way adjustable, Granatelli Motorsport Subframe

[This message has been edited by HAITHAM (edited 09-04-2001).]

08-29-2001, 11:07 AM	#1
Jeff7477 Registered Member Join Date: Jun 2001 Location: Lincoln, Nebraska USA Posts: 67	Bad Idle Trouble I am having some problems with the way my car runs. When its cold, It will start, and idle good for a couple seconds, then hesitate and drop to under 500 rpms, then regain itself. It does this till its warm, and it stops. Also, Sometimes the car will idle above 1000 rpm until you stop and restart the engine. What going on?

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08-29-2001, 02:01 PM	#2
Sneaky Registered Member Join Date: Aug 2001 Location: Baytown, Tx. USA Posts: 25	What year Mustang do you own? If it is a 87-88 speed density I would check the idle air bypass valve. What mods do you have? Need more info.

08-29-2001, 02:40 PM	#3
95mustanggt Registered Member Join Date: May 2000 Location: Kamloops, BC Posts: 2,875	You're going to have to give a little more information on your car before anyone can give you some help. ------------------ 1995 Mustang GT

08-29-2001, 03:46 PM	#4
posied88 Registered Member Join Date: Aug 2001 Location: Anaheim, Ca. Posts: 31	I have somewhat of the same problem. It idles around 1000 and then drops to about 500.It does almost anytime though. When I'm at a light I sometimes have to give it gas or else it will die. I dont know what it is but I recently installed an off-road H-pipe, and it never had that problem before. I thoght it was my cam at first because it did it before but very little like when it was hot or cold. I also thought it may be my timing.maybe someone out there can help me with a solution or something. Thanks. ------------------ 3.55 gears,posi,mac 1 5/8 shorties,off-road h-pipe,w/flowmasters,bbk 65mm throttle body,frpp aluminum driveshaft,frpp b303 cam,hurst short throw shifter.

08-29-2001, 05:56 PM	#5
Jeff7477 Registered Member Join Date: Jun 2001 Location: Lincoln, Nebraska USA Posts: 67	Its a '90 and only things are headers, h-pipe, and cat-back

08-29-2001, 08:31 PM	#6
exgmguy Registered Member Join Date: Feb 1999 Location: Utica, Michigan Posts: 2,631	Clean the idle air motor, check the TPS, and reset the computer. ------------------ 1988 Mustang GT 11.8 @ 123 (7/14/01) 1992 BadAzz Wrangler 1993 Explorer See my car at: www.mustangworks.com/cgi-bin/moi-display.cgi?179

08-29-2001, 11:09 PM	#7
gofastmercury Registered Member Join Date: May 2001 Location: calgary alberta canada Posts: 366	When my 93 did that, I cleaned the throtle blade. It has a little hole in it, and if it plugs, the idle goes wonky. ------------------ 93LX excopcar 150K 3.55's mac full headers. funnest car I ever had. 14.3@96 @ 4000ft 67 390 ranchero 3.70's cast manifolds, comp cams 260H, completly stock 15.1@90mph 66 merc comet 351w, isky roller 600 lift 268/260@.050, vic jr. 700DP, 5000stall, 4.56's c-4, 3400lbs with driver

08-30-2001, 12:22 AM	#8
posied88 Registered Member Join Date: Aug 2001 Location: Anaheim, Ca. Posts: 31	Thanks guys Ill look into those things.

09-04-2001, 06:48 AM	#9
HAITHAM Registered Member Join Date: Jun 2000 Location: Saudi Arabia Posts: 130	There are any improvement ????? ------------------ 94 COBRA # 926/5009 TFS track heat heads (ported), Cobra intake (ported), 24# Injectors, 3/8" Phenolic spacer, E303 Cam, TFS 1.7 rr BBK 1 5/8" headers, BBK 65mm TB, Pro-M 80mm MAS, PIH kit w/ A9L computer, FMS 3.55 ratio BBK 190 lph fuel pump, Paxton fpr, MSD'S, March Pulley's, Pro-5 tower power shifter, Autometer shift light (5600), Intellitronix Air/Fuel gauge, Eibach Sportline Springs, Tokico 5-way adjustable, Granatelli Motorsport Subframe [This message has been edited by HAITHAM (edited 09-04-2001).]