Mustang won't start

FlatBlackFiveOh

Founding Member
Nov 1, 2002
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In my car
The car is a pretty much stock 1999 Mustang GT. The other day (thursday I think) it was running perfectly fine when I went to work in the morning, and then after work it would not start. It will start, then revv up real high and die, then the gauges all reset. Sometimes it will idle at ike 15 RPM, and it backfires through the exhaust, but even more through the intake. If I start it and push the gas, nothing happens, unless I go to full throttle, then it revvs, but nothing at part throttle, then dies. It did the same thing when leaving a restaraunt a few days earlier, but then after a while corrected itself and ran fine.

I towed the car to my house so it's not in the way at least, and got to trying to find the problem. I ran a code scanner on it, and only got 2 codes. One for no cats (been that way for years) and one for IAT Sensor Low Impedance. The wire leading to the IAT sensor (the little sensor after the MAF) was broken, and I thought maybe this could be the problem since it's so hellaciously cold out, but it has been broken for a while I THINK. But this morning I fixed that, and the car still won't run.

It sounds almsot exactly like a car with the timing WAY WAY off, but it's all computerized, so how the hell does this happen?? I've ruled out a jumped cam chain, because it wouldn't have happened while the car was off and it wouldn't explain why the problem occured earlier than fixed itself. So it has to be electronic, but with all this computer **** I'm out of stuff I can check.

So, have any of you seen a similiar problem, or have any ideas for stuff I should check?

And here's the longshot question. If I can't find the problem soon, is there anyone out there in Chicago who would lend me a trailer to tow the car to my school so that I can get my teacher to look at it or use different testing tools? When I towed it home I used a rented tow-dolley from U-Haul, but don't care to do that again.

Thanks for any information you may provide...
 
FlatBlackFiveOh said:
is there any way I can test it? Could not knowing the air temperature really cause it to run THAT bad? Really shows how superior carbureted engines are.. :-p
My 99 did the same thing start it and quit. My would quit going down the road.
 
FlatBlackFiveOh said:
Do you know if there's a way to test the sensor though. Or maybe bypass it just tos ee if it starts? How much does this sensor cost?
I do not know how to test it. I think it cost like 50 or 60 dollars. Call the ford dealer and ask the service department.
 
Take it off and clean it (IAC). It should work after spraying it with a carb cleaner. I would try this first before buying a new one although it may be you will have to get one soon anyway.
 
just get a new IAC, i dont think a low impedience on an Intake Air Temp sensor would cause a car to stall like that. i got one for my grand marquis from a dealer for like $45 with an employee discount, but it should be about 60-70 from a dealer, less from napa or someplace like that. on a stang its easy to take off and easy to install yourself.
 
Lemme make sure you we are reffering to the same thing. Is the IAC the little sensor between the MAF and the Throttle Body? I have been calling that an IAT... Before spending $70 on a new sensor I'd like to make sure it's the problem though. I wonder if Ford would return it if it doesn't fix the car.
 
FlatBlackFiveOh said:
Lemme make sure you we are reffering to the same thing. Is the IAC the little sensor between the MAF and the Throttle Body? I have been calling that an IAT... Before spending $70 on a new sensor I'd like to make sure it's the problem though. I wonder if Ford would return it if it doesn't fix the car.
The IAC is on the upper plenum on the front of it.
 
Scientific test for your IAC when the car will not start.

Get a screwdriver, hold it by the metal part and whack the IAC a couple of times.
crank your car and replace as soon as possible.
You first need to make sure you know what the IAC is. :nice:
 
Here is what you are looking for.
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The IAT is just a thermister. To test it, monitor the resistance while you hold the element and the resistance should change. I seriously doubt that is causing your problem. A bad vacuum leak or problem with the IAC is possible as is water in your gas. Good luck. :nice:
 
I took the IAC off and cleaned it. Then plugged it in and turned on the ignition with it still unbolted, and I felt it try and actuate but it didn't look like the rod inside moved. I dunno if that is normal. It didn't fix it. But with the IAC un plugged it isn't much different. Seemed to idle a little higher, but still revved itself when started. How can it do that, the IAC and the TB are the only things that can let air in....