1993 Ford Mustang stalls when driving

ford
mustang

#1

Why does my car stall while I am driving it?


#2

Something is obviously wrong.

How about describing your car - mileage, engine size, transmission type

And then describing in detail the conditions around which the car stalls.


#3

1993 fox body, 2.3 4 cylinder, 160,000 miles, automatic transmission that has been rebuilt.
Once I get around 55 mph I lose power until I get back down to around 45, and then it will suddenly kick in and accelerate again. During this time it will backfire out of the engine compartment and not out of the exhaust. The transmission isn’t slipping, so I know that’s not the problem. Sometimes it becomes a huge problem when I have to slow down to turn, because it will spit and sputter and hardly move for a long time until eventually the acceleration kicks in. I had the car at the shop and they couldn’t test it because it didn’t mess up while they were driving it. It is totally random when the car messes up. Sometimes it is really bad, and sometimes it is fine.
I appreciate your help! Thank you


#4

You have a tricky issue on an older car that is going to take some good diagnostic work to sort out.

That is often a symptom of lean fuel condition but it can also be an ignition issue.

Since a mechanic has looked at the car I will assume the fuel lines are OK and there are no obvious wiring issues and that they have checked relays and fuses for flaky contacts.

Attaching a fuel pressure gauge and taping it to the windshield so a mechanic riding along can see what it is doing will either confirm or deny it is a fuel issue. If the pressure drops, I’d suspect an electrical problem with the fuel system. I’d repeat the condition with a voltmeter or test light across the fuel pump terminals so you can see if power for the pump is cutting out. If it is, I’d carefully check the impact switch in the trunk - a device to cut off the fuel pump if you get in an accident - or bypass it temporarily and re-test.

If the fuel pump is not the issue, I’d be looking to see if the motor mounts are allowing too much movement and shorting out or over stressing a wire needed by the ignition.

If you aren’t going to do this yourself, you need to find, and expect to pay for the time of, a mechanic who likes to do diagnostic detective work. Pretty much NOT the guys you’ve had work in it until now. Good Luck!