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Old 10-21-2007, 05:25 AM
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1988 mustang GT stalling

I just bought a 1988 mustang GT with fuel injection and an aod transmission. I drove it home for about a half an hour with no problems at all. By now, the gas was pretty low (the gauge read 1/16-1/8 of a tank). Later on that day, i took it for a quick 10 minute ride and the engine just died at about 40 mph. I pulled over on the side of the road and sat for a few minutes. I started it back up and managed to get home, but it died a few times on the way home. When I let the car sit in my driveway and idle for any more than 2 or 3 minuted, the RPM varies and sort of pulses like it's going to stall. It sometimes does stall. When I put the car into reverse when it's idling normally, the RPM drops way down and the car normally stalls. If it doesnt stall, it's on the verge of stalling(idling at very low RPM while pulsing). Does anyone know what the problem could be? Thanks for the help.

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Old 10-21-2007, 06:58 AM
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My brothers did that after he purchased his.He found that the front leading edge of his upper intake had been overtorqued and broken,allowing a major vacum leak.Instead of buying a new one,he J.B Welded it.I never would have believed it,nor recommended it,but sometimes you do what you can.
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Old 10-21-2007, 10:38 AM
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I can't see any broken pieces of the manifold or anything missing. I just changed the fuel filter because the fuel pump was pretty loud like it was working too hard. The pump is definitely quieter but the throttle still pulses. Any other suggestions? The gas tank must have a hole or something in it, also. I think it's on top because there are drip marks from up there. how would I look for the leak? It's real tight up there. Thanks for the help
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Old 10-21-2007, 11:22 AM
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It would be best to drop the tank.The pump secures to a complete assembley that secures to the tank with a ring.You may have a rubber fuel line that has split,but I have also seen the hard lines rupture due to rust.
You may get lucky and angle a mirror on a stick up there and direct the beam from a flashlight just right.But still probably end up dropping the tank,which is not hard as long as the tank is not full of fuel.Good Luck.
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Old 10-21-2007, 11:27 AM
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Quote:
Originally Posted by awoodman
I just bought a 1988 mustang GT with fuel injection and an aod transmission. I drove it home for about a half an hour with no problems at all. By now, the gas was pretty low (the gauge read 1/16-1/8 of a tank). Later on that day, i took it for a quick 10 minute ride and the engine just died at about 40 mph. I pulled over on the side of the road and sat for a few minutes. I started it back up and managed to get home, but it died a few times on the way home. When I let the car sit in my driveway and idle for any more than 2 or 3 minuted, the RPM varies and sort of pulses like it's going to stall. It sometimes does stall. When I put the car into reverse when it's idling normally, the RPM drops way down and the car normally stalls. If it doesnt stall, it's on the verge of stalling(idling at very low RPM while pulsing). Does anyone know what the problem could be? Thanks for the help.

I had an 88 mustang gt that pulsed at idle. It was the TPS(throttle position sensor)
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Old 10-21-2007, 11:43 AM
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Fuel or Fire

I would suggest try to diagnose before you replace parts. The TPS is a good guess, and it may actually be. If you have an ohm meter and a volt meter, 1st check the resistance on the sensor, if it checks ok, check your signal to it (is it getting corect voltage). As far as fuel delivery goes, run it till it dies, pull the fuel line from the motor, check fuel pressure and flow (a bad fuel electric fuel pump will die when it starts to warm up from running). As far as ignition goes, I would just pull a plug and check spark These are just a few suggestions....take them for what they are worth.
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Old 10-21-2007, 12:20 PM
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had a similar problem with a blazer I had bought. Drive it for about a half hour and it would die, sit it for a minute and it would start go a little and die, eventually it would take a few hours before it would start back up and then I'd be able to drive it agian for about a half hour before dieing. Would run rough at times also while ideling.

After a bunch of needless stuff it ended up being the distributor, had to be replaced or rebuilt forget which.
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Old 10-21-2007, 01:15 PM
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I'll check the TPS, now. What is the resistance and voltage supposed to be when the throttle is at a certain position? What is that position? Im guessing I check the voltage and resistance when the car is off? How exactly do I drop the tank? How do I drain it? After draining it, I imagine I'd pull the line going from the tank to the filter, off of the filter. Then what?
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Old 10-21-2007, 01:55 PM
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I Just checked the TPS sensor's voltage. It's getting .984 when the car is off but the key is turned to on. Is that a good figure?
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Old 10-21-2007, 03:22 PM
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I just turned the idle to about 650 RPM and it doesn't pulse so i don't care what the hell it was-lol. But thanks for the help. I still do have to fix the tank.
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Old 10-24-2007, 10:54 PM
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.984v is OK. It should sweep smoothly up to 5.0v or slightly less as you open the throttle.

Before you go spending big bucks and doing a bunch of work, go get a $4 spray can of throttle body cleaner. Remove the plastic air pipe from the throttle body. Be careful you don't screw up the rubber seal, because you can't by a new one without buying the whole tube for ~$50. Spray the dark gunk off the throttle blade edges, and shoot some into the idle air controller passages in the front of the throttle body bore a few times. Wipe out what you can with a clean rag, and hose it down again.

It might not start instantly once you get it buttoned back up, and it probably won't run worth crap for a few seconds until all that solvent gets burned out. Rich mixture, you know.

I've had to do this on my '88 T-bird about every 50,000 miles when the idle would get really unstable. At 170K, the TPS went screwy and caused major bucking, but it would idle pretty well.

Have you asked the computer if it knows what's wrong? I ask this because my TPS tested seemingly smooth from .89 to 4.something, but the computer said it was faulty, and a sensor from a used Lincoln made it run fine.

Last edited by jimfulco; 10-24-2007 at 11:00 PM.
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Old 10-24-2007, 11:39 PM
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Check the computer for codes. 14 /18 codes will be a ign. problem pretty much meaning it will need a new stator (pick up coil) in the dist. Its always best to change the module when you change the stator. That issue could account for stalling at speed then after cooling down, restarting. Do you know how to check codes with a test light? Google it or write back and I can give you a link if it still works.

For the stalling at idle issue, clean the throttle body like Jim said. A dirty egr valve can cause a similar problem at idle. Make sure the egr is clean. Carbon buildup can cause it to stay slightly open causing stalling. After cleaning the EGR disconnect the battery for 5 min then hook it back up, restart the engine, reset the idle to 800 rpm (650 in drive). Since you messed with the idle screw you need to reset it back to the original setting because by adjusting it up you have changed the base reading of the TP sensor. Speaking of the TP sensor the sweep is the most important check to be made. Its best to see on a analog meter but you can watch it on a digital. If there is ANY erratic movement in the needle of numbers you must change the TP.

Check the EGR sensor with the ohmmeter also. An erratic signal from the sensor will also "confuse" the computer causing stalling. To drain the tank you can drive it until its about an 1/8 tank, or run a hot wire to the fuel pump relay or to the inertia switch (you will need a wiring diagram for this), disconnect the fuel line at the engine and run the gas into a tank. You need to remove the tank to properly service the leak. Possible problem areas: connector end, plastic line, cracked tank, O ring. You need to drop it to check it out. Removing the tank looks harder than it is. You WILL need a new o ring if you remove the pump.

Last edited by 2-manytoyzs; 10-24-2007 at 11:54 PM.
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Old 10-25-2007, 05:02 PM
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Okay, thanks, Im going to get a hold of a computer to hook up to the car to check for codes. Ill clean the valve and air sensor, too.
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Old 10-25-2007, 10:22 PM
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The site I used to go to for EEC codes is no longer on the net so I Googled Ford EEC self test codes and the first site I went to had a good explanation of how to perform a self test with a test light and a jumper wire. You need to learn this if you are going to own a Ford and maintain it yourself. Once you learn this procedure it is easy to read and understand the codes. If you don't get it the first time don't feel bad. It took me a long time and I was working at a Ford dealer at the time.

Link:

www.fordfuelinjection.com click - how to run a self test

BTW The best way to check the egr and tp sensors is to disconnect the sensors and/or remove the sensors and check them with the ohmmeter. With the sensor disconnected probe the terminal connections in the sensor. If the ohmmeter doesn't change when moving the sensor (egr) or shaft (TP) try another combination of terminals until you get the two that cause the needle to sweep (analog). Again, any erratic movement will confuse the computer. No servicable parts, replace the sensor if necessary.
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Old 11-14-2007, 12:12 PM
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1988 GT mustang

CHECK THE tsp the voltage should read .900 between .950 mv
also if it has mass air flow if you don't match up the injectors with the flow meter it will stall at idle. METER AND INJECTORS must be cal. together
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