1994 Ford Probe SE Starting/idle/throttle Issues?Gremlins?

Tiny
TBINS
  • MEMBER
  • 1994 FORD F-250
First things first,

1994 Ford Probe SE
2.0L, 4 Cyl. Engine
145,000 miles
New 4 Speed Automatic Transmission (done at about 142,000 miles)
New Radiator (small coolant leak somewhere)
Recent Tune up.
New Air filter
New Fluids

Problem:

(This is a strange one)
It will start up fin cold. It'll run fine. But after it warms up, if you stop and put it in neutral the engine rpms sky rocket (as high as 5000+). Shut it off and turn it back on and the rpms will skyrocket again (in both Park and Neutral). Drive, Reverse, 1st, 2nd and OD/OFF all work fine, engine runs a little rough and idles at 750 to 1250 (varies but usually at 1000). Have adjusted the idle speed screw a few times, have gone to a pull yard and got a different throttle body but still have the same problem. If the rpms drop below 500, the car stalls out. Once in a while, it wont start at all.

Last time we test drove it to see if we had fixed the problem, when we got back, white smoke was coming out form under the hood and upon closer examination, we saw that it was coming form a hose connected to the throttle body (I am assuming that it is where the coolant goes in to the temp sensor in the throttle body).

PLEASE HELP. None of the mechanics I know have ever hear of a car doing this.
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Thursday, June 7th, 2007 AT 8:35 PM

9 Replies

Tiny
METAL_DISASTERPIECE
  • MEMBER
I used to have a 1996 SE with the same problem, it was my Idle Air Control Valve, try replacing it. Hope it solves your problem.
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Friday, June 8th, 2007 AT 12:43 AM
Tiny
TBINS
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I was afraid of that (but somehow I knew it all along), as they aren't cheap. About $500 last time I checked. Ok, thanks for the tip. I'll try replacing it and see what happens
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Friday, June 8th, 2007 AT 11:56 AM
Tiny
METAL_DISASTERPIECE
  • MEMBER
Hey u can get the ford probe IAC Valve on ebay for less than $100.
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Friday, June 8th, 2007 AT 3:06 PM
Tiny
TBINS
  • MEMBER
Thanks! Looks like I'll be saving about $315. Autozone wants $504 for a new one and ebay wants $190. Thanks so much guys.
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Friday, June 8th, 2007 AT 7:37 PM
Tiny
TBINS
  • MEMBER
Sadly, after replacing the Throttle body with a remanufactured one form Ebay, the problem persists. It just doesn't make any sense.

It'll run fine for the first 2 or 3 miles, then the engine starts acting up. The rpm's don't drop after I take my foot off of the gas (until I push the break); it goes from idling at between 750 and 1000 to idling at 1500 and surges when I put it in park or Neutral.

I suspect a vacuum leak or an other electronic component has gone bad. No idea. I did find out that the thermostat was bad (and had a bad gasket) and replaced that, but it didn't help.

Please, if anyone out there has any ideas (besides taking it to a garage. I'm gonna do that as soon as I get paid again.) PLEASE HELP
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Saturday, June 30th, 2007 AT 4:26 PM
Tiny
98RANGERXLT
  • MEMBER
Your throttle position sensor may be bad.
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Saturday, June 30th, 2007 AT 5:02 PM
Tiny
TBINS
  • MEMBER
I ran a volt test on my TPS and it checked out fine as far as I can tell.

I also ran a volt test the MAF and that seemed fine.

I'm taking it to a shop next week (July 9) for diagnostics.
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Monday, July 2nd, 2007 AT 12:26 PM
Tiny
TBINS
  • MEMBER
I just heard back from my mechanic. There was a couple of cracked vacuum tubes on the passenger side of the intake manifold and the Idle Air Control Motor (not sure what or where that is. I think it's part of the IAC valve or the TPS) is sticking. It's gonna be about a $400 job to fix it all if the motor doesn't need to be replaced.
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Monday, July 9th, 2007 AT 12:56 PM
Tiny
TBINS
  • MEMBER
Correction.

My Intake Manifold Gasket was cracked and there was some instant silicone gasket that had seeped into the Idle Control Motor on the throttle body and was causing it to stick open. They also replaced some bolts that were loose and stripped and now my car runs like New.
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Friday, July 13th, 2007 AT 11:34 AM

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