1991 Mustang 2.3L

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I have a four cylinder 1991 mustang lx, I was driving on the freeway and boom I lost power, couldnt get above 50 miles and started smelling real bad. I had the pedal to the floor and just bogging down terrible, shaking and then I pulled over. Looked under the car and the first catalytic converter and exhaust pipes into the engine were red hot. Took it to the mechanic and it did it again, we tested the coil packs and found a cylinder was gone, we got some used but working coil packs and put them on, replaced the fuel filter, and it seemed to work for awhile, then it did the same thing to my wife about a month and a half later. Replaced the plug wires and plugs, car responds great but after it heats up it drops a cylinder again. Once it cools off I can drive it like normal. No error codes show up on the computer. Kinda stuck as to what to do next.

posted by  jobs50

At this point, before doing anything else, you need to check the cat for blockage. If it was "red hot" it has probably collapsed inside and will need replacement before you can go any farther with the diagnosis.

posted by  vwhobo

There are two cats on this car and the first one that was hot has been drilled and cleaned, leaving one cat intact.

posted by  jobs50

Oh, another one of those that leaks out information as he see's fit. Good luck getting help.

posted by  vwhobo

Just today we had a bit more info to add, I started the car when it was right cold and the cylinder was not firing, so that eliminates the the heat issue, my dad and I also figued out it was cylinder # 1 'cuz we tried to start it with #2 plug wires off and it didnt go, then we took off #1's and it went just the same as when they were on, idling really hard. So I am not sure if I should go and look for a new DIS (distributerless ignition system) or does it have to do with the computer?

posted by  jobs50

I think you should just get rid of it. No one should own a 4 cylinder mustang.

posted by  Sonreir

Well the car is fixed, I got the DIS replaced and that solved my problems, no more misfires. Thanks for all your help.... :orglaugh:

posted by  jobs50

You found the problem with some troubleshooting.

I would still make sure the cat that is remaining does not become blocked. Running a car as long as you did with a dead cylinder pushes a lot of raw fuel into the exhaust system.

I would also be careful about drilling out cats. Technically, drilling out the cats is tampering with and disableing the emmission control equipment on a car which is a violation of Federal Law.

posted by  tbaxleyjr

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