Ok. Here’s one for ya. I have a 1988 5.0 H.O. LX Hatchback 5 Speed and a 1993 5.0 H.O. LX Hatchback AT (one for each foot). Lately (within the past year), when the air temperature here in Las Vegas gets above 100 degrees F, my favorite 1988 Baby does this strange thing. It stops running. It will have been purring along for hours and then decide it’s finished doing that and the engine simply stops running. It’ll happen at any speed. 75 mph. 25 mph. Idling. There is no tell-tale warning or idiosyncrasy before it happens. It just quits. It feels like someone has yanked all the plug wires off of the plugs. The engine is at its usual cool running self and not even close to overheating. I have no ac, so it’s not on. I am dead in the water. I’ve learned, from its having happened so many times, that if I let the car cool down (which means waiting for the Vegas sun to go down) I can come to it, crank it up and drive away like nothing had happened to it. Runs like the champ it is. So, here’s what I’ve started doing to eliminate the problem. (1) New Igntion Module. (2) New Coil. No change. Next comes (3) New Pickup Coil. (4) New Rotar. (5) New Distributor Cap. (6) New Plug Wires. (7) New EEC-IV Computer. The first thing I checked, after it happened the first time, was an interruption in the fuel supply. That wasn’t it. It also had a new pump in the tank. In my gut, I feel it’s the EEC computer getting hot under the dash and going belly up. I haven’t had the opportunity to pack the EEC in baggied ice and see if it still happens. What do you all think is the problem?

 

sounds like it might be your ignition switch...or your TFI...just because its new doesn't mean it works

 

I don't know, but I recently just solved my dying issues. I replaced the ignition switch and lock cylinder, total of $33... It might be worth a try, my ignition switch was busted and the contacts were worn inside. One thing to clarrify, does your radio turn off when the engine does?

 

How about the relay that controls the fuel pump..........I had a simular problem on an 88. If I remeber correctly it is down there by the computer.

 

Ignition switch & cylinder Ok. Thanks TenGram & gr84u.
Fuel Pump, etc. Ok. Thanks Randy.

Old John

 

its definitely the TFI

 

lookingforastang,

The ignition module (TFI) has been replaced by a remanufactured module. Thanks.

Old John

 

One thing to narrow it down, when it quits, have you checked for spark or fuel pressure? That would definitely let you know which system is failing. I agree that initial impression is electronic failure in the ignition system. When you replaced the TFI, did you use the grease on the plate on it?

 

the relay is under the drivers seat

 

I had a similar thing happen to my 5.0. It ended up being the coil inside of the distributor, I ended up just pulling and replacing the distributor, the job was alot easier than it sounded, havent had the problem since, hope it helps..