High idle speed out of no where.

SlowStang2 · 07-10-2001, 08:04 PM

On my way to school this afternoon, it was raining hard. I went through a few deep puddles. Everything was FINE on the way to school. Car shut down fine and everything. I come out 3 hrs later and start the car and the idle shoots to 2500 and stays there. WTF

I get to a light, put it in neutral, the damn thing stay up at 2500 until I come to a complete stop then it goes down to 1300. Check Engine light comes on. I get home, open hood, NOTHING WRONG. NOTHING is wet. Even the air filter is dry. I moved the idle and IAS screws down and little imporvement. What the hell happened? Don't tell me something just broke just because. Right now the battery is disconnected. Any suggestions?

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94' Stang GT Convertible Cobra upper&lower, Mac cold air w/K&N, BBK equal length shorties, BBK offroad H-pipe, American Thunder cat-back, BBK T/B 65mm, 24lb injectors, Pro-77mm MAM, pulleys, aluminum driveshaft, 3.55s 14.4@100. (Sad, i know. i have stock heads)

Stang Runner · 07-10-2001, 09:02 PM

Check the pvc valve.. And look for any vacuum hose not on. And check your TPS too.

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1988 LX 5.0 Was 3060lbs (full Tank) 14.65@103.5 On a Gtech Drivetrain: 3.55, World Class T-5, Lakewood Bellhousing, Adjustable Cluch Cable, AL Driveshaft, Manual Steering Rack Suspension: MAC Control Arms,Maximum Motorsports Front Grip Package, H&R Sport Spings, Bilstein Shocks
Engine: Steal Mounts, K&N, Under Drive Pulles Exhaust: 1 5/8 Un-Equal Length Mac Headers, X-pipe W\cats, Edelbrock cat\back Cooling:3 Core Radiator,

Jeb_Bush_2000 · 07-10-2001, 09:20 PM

That used to happen to our old Explorer. I think it was a computer problem related to the moisture in the air.

SlowStang2 · 07-10-2001, 09:28 PM

pvc valve is ok. and all hoses are on. Jeb-did the problem go away after a while? it has been raining hard here and it is humid, but this all sounds so unrealistic.

------------------
94' Stang GT Convertible Cobra upper&lower, Mac cold air w/K&N, BBK equal length shorties, BBK offroad H-pipe, American Thunder cat-back, BBK T/B 65mm, 24lb injectors, Pro-77mm MAM, pulleys, aluminum driveshaft, 3.55s 14.4@100. (Sad, i know. i have stock heads)

Jeb_Bush_2000 · 07-10-2001, 10:19 PM

Well, it seemed to happen every time it rained. It would also stall unless you gave it about 1/4 throttle, and every time you stopped, it'd stall. Warming up the car didn't help. However, it didn't always jump to a high idle; it seemed to only do that after you stalled and restarted it a few times.

I don't know if this has anything to do with your problem, but they're both Ford products from the same era....

jimberg · 07-10-2001, 10:25 PM

If the check engine light comes on, check the codes before you do anything else. Now your idle probably is screwed up since you messed with the idle screw. You're TPS is now probably off, too.

Get a code reader if you don't have one, or create a wire with a spade on each end and jumper the test lead to the diagnostic connector. Read this article Corral.Net: EEC-IV Testing.

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351W 89 Mustang GT Convertible

elma22 · 07-11-2001, 01:59 AM

I had a simular problem on my 88 GT, as it turned out my TPS was not functioning properly. After I replaced it everything worked fine. TPS will always show you some voltage so it is kind of pain in the but to determine whether you need a new one or not. Give it a try.

SlowStang2 · 07-11-2001, 03:30 PM

I took it to a shop to get the codes. A code came up saying, yes, the TPS is bad. Now I have been through something like this before(finding out the problem, fixing it, when it was just another problem instead), but I'm getting the replacement tomorrow. I don't like how it just failed for no reason though.

------------------
94' Stang GT Convertible Cobra upper&lower, Mac cold air w/K&N, BBK equal length shorties, BBK offroad H-pipe, American Thunder cat-back, BBK T/B 65mm, 24lb injectors, Pro-77mm MAM, pulleys, aluminum driveshaft, 3.55s 14.4@100. (Sad, i know. i have stock heads)

Jeb_Bush_2000 · 07-11-2001, 03:33 PM

Slowstang, I have a question for you.

You have a cold-air induction kit. Did you install that along with a bunch of other mods? I was thinking of getting one and I'm curious as to what sort of difference it makes if I'm not going to be racing.

SlowStang2 · 07-11-2001, 03:43 PM

Jeb-its made from Mac and I did purchase piece by piece the rest of the intake, MAM, TB, and i did feel a difference with just the cold air kit, but i dont know it is better than lets say March's Ram air system.

------------------
94' Stang GT Convertible Cobra upper&lower, Mac cold air w/K&N, BBK equal length shorties, BBK offroad H-pipe, American Thunder cat-back, BBK T/B 65mm, 24lb injectors, Pro-77mm MAM, pulleys, aluminum driveshaft, 3.55s 14.4@100. (Sad, i know. i have stock heads)

07-10-2001, 08:04 PM	#1
SlowStang2 Registered Member Join Date: May 2001 Location: Stuart, FL, US Posts: 147	High idle speed out of no where. On my way to school this afternoon, it was raining hard. I went through a few deep puddles. Everything was FINE on the way to school. Car shut down fine and everything. I come out 3 hrs later and start the car and the idle shoots to 2500 and stays there. WTF I get to a light, put it in neutral, the damn thing stay up at 2500 until I come to a complete stop then it goes down to 1300. Check Engine light comes on. I get home, open hood, NOTHING WRONG. NOTHING is wet. Even the air filter is dry. I moved the idle and IAS screws down and little imporvement. What the hell happened? Don't tell me something just broke just because. Right now the battery is disconnected. Any suggestions? ------------------ 94' Stang GT Convertible Cobra upper&lower, Mac cold air w/K&N, BBK equal length shorties, BBK offroad H-pipe, American Thunder cat-back, BBK T/B 65mm, 24lb injectors, Pro-77mm MAM, pulleys, aluminum driveshaft, 3.55s 14.4@100. (Sad, i know. i have stock heads)

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07-10-2001, 09:02 PM	#2
Stang Runner Registered Member Join Date: Jun 1999 Location: Walker, MI, USA Posts: 1,202	Check the pvc valve.. And look for any vacuum hose not on. And check your TPS too. ------------------ 1988 LX 5.0 Was 3060lbs (full Tank) 14.65@103.5 On a Gtech Drivetrain: 3.55, World Class T-5, Lakewood Bellhousing, Adjustable Cluch Cable, AL Driveshaft, Manual Steering Rack Suspension: MAC Control Arms,Maximum Motorsports Front Grip Package, H&R Sport Spings, Bilstein Shocks Engine: Steal Mounts, K&N, Under Drive Pulles Exhaust: 1 5/8 Un-Equal Length Mac Headers, X-pipe W\cats, Edelbrock cat\back Cooling:3 Core Radiator,

07-10-2001, 09:20 PM	#3
Jeb_Bush_2000 Registered Member Join Date: Jul 2001 Location: Taxachusetts Posts: 374	That used to happen to our old Explorer. I think it was a computer problem related to the moisture in the air.

07-10-2001, 09:28 PM	#4
SlowStang2 Registered Member Join Date: May 2001 Location: Stuart, FL, US Posts: 147	pvc valve is ok. and all hoses are on. Jeb-did the problem go away after a while? it has been raining hard here and it is humid, but this all sounds so unrealistic. ------------------ 94' Stang GT Convertible Cobra upper&lower, Mac cold air w/K&N, BBK equal length shorties, BBK offroad H-pipe, American Thunder cat-back, BBK T/B 65mm, 24lb injectors, Pro-77mm MAM, pulleys, aluminum driveshaft, 3.55s 14.4@100. (Sad, i know. i have stock heads)

07-10-2001, 10:19 PM	#5
Jeb_Bush_2000 Registered Member Join Date: Jul 2001 Location: Taxachusetts Posts: 374	Well, it seemed to happen every time it rained. It would also stall unless you gave it about 1/4 throttle, and every time you stopped, it'd stall. Warming up the car didn't help. However, it didn't always jump to a high idle; it seemed to only do that after you stalled and restarted it a few times. I don't know if this has anything to do with your problem, but they're both Ford products from the same era....

07-10-2001, 10:25 PM	#6
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	If the check engine light comes on, check the codes before you do anything else. Now your idle probably is screwed up since you messed with the idle screw. You're TPS is now probably off, too. Get a code reader if you don't have one, or create a wire with a spade on each end and jumper the test lead to the diagnostic connector. Read this article Corral.Net: EEC-IV Testing. ------------------ 351W 89 Mustang GT Convertible

07-11-2001, 01:59 AM	#7
elma22 Registered Member Join Date: Jul 2001 Location: Montreal Posts: 45	I had a simular problem on my 88 GT, as it turned out my TPS was not functioning properly. After I replaced it everything worked fine. TPS will always show you some voltage so it is kind of pain in the but to determine whether you need a new one or not. Give it a try.

07-11-2001, 03:30 PM	#8
SlowStang2 Registered Member Join Date: May 2001 Location: Stuart, FL, US Posts: 147	I took it to a shop to get the codes. A code came up saying, yes, the TPS is bad. Now I have been through something like this before(finding out the problem, fixing it, when it was just another problem instead), but I'm getting the replacement tomorrow. I don't like how it just failed for no reason though. ------------------ 94' Stang GT Convertible Cobra upper&lower, Mac cold air w/K&N, BBK equal length shorties, BBK offroad H-pipe, American Thunder cat-back, BBK T/B 65mm, 24lb injectors, Pro-77mm MAM, pulleys, aluminum driveshaft, 3.55s 14.4@100. (Sad, i know. i have stock heads)

07-11-2001, 03:33 PM	#9
Jeb_Bush_2000 Registered Member Join Date: Jul 2001 Location: Taxachusetts Posts: 374	Slowstang, I have a question for you. You have a cold-air induction kit. Did you install that along with a bunch of other mods? I was thinking of getting one and I'm curious as to what sort of difference it makes if I'm not going to be racing.

07-11-2001, 03:43 PM	#10
SlowStang2 Registered Member Join Date: May 2001 Location: Stuart, FL, US Posts: 147	Jeb-its made from Mac and I did purchase piece by piece the rest of the intake, MAM, TB, and i did feel a difference with just the cold air kit, but i dont know it is better than lets say March's Ram air system. ------------------ 94' Stang GT Convertible Cobra upper&lower, Mac cold air w/K&N, BBK equal length shorties, BBK offroad H-pipe, American Thunder cat-back, BBK T/B 65mm, 24lb injectors, Pro-77mm MAM, pulleys, aluminum driveshaft, 3.55s 14.4@100. (Sad, i know. i have stock heads)