Dockboy19

Recently bought a 89 Gt, previosuly had a 87 GT. Never had a problem with coils. 89' drove it for 3 days no problems, park it one day go to start it like a hour later and nothing. Go and buy another coil, starts runs for like 20 mins then dies. I am lost with this car. Any help at all would be nice.

90GTRagtop

Are you sure the coil is bad? Use an ohm meter or the ohm function on a multimeter and check the resistance on both sides of the coil. I have gotten coils before that didn't last much out of the box, but not ususally. Might also need to check the TFI (Thin Film Ignition) module. Have you tried pulling any codes from the computer with the Key On Engine Off test? Do you have any mods that could be cutting it out? Especially, did someone before you have an alarm system that could be cutting it out?

GT350Stang

i had the same problem. what mine was doing is that i had the wrong resistance in the coil and so what it was doing is melting the coils together and it would run for like 30 minutes and then die. so i just went and bought a MSD blaster 2 coil and i have not had a problem since

Dockboy19

I talked to some people and they said it might be the Ignition control module??

stanglx2002

sounds like the ingition module is getting hot and shutting the car off. The ingition module has to has thermal grease on the back of it or it will get hot and shut the car off

Pure5.0

Where is the ignition module located at?

stanglx2002

on the front of the distrubutor

P.S.I.cho

in my 95' there is a sensor in the dist (magneto), when this goes bad u usually have to replace tfi too.

86HOGT

Would a worn out pickup and/or TFI create random misfires, yet still run strong off idle?

90GTRagtop

Yes it could, by the very definition of what you said. If it's random, then the odds are that it would happen most often in the normal condition of the motor, which would be under throttle going down the road (most of the time), followed by idle (sitting at lights etc.), and lastly by acceleration or deceleartion periods (least amount of time). All that said, if it's breaking down when it gets hot, it may well perform fine when it's cool.