I have replaced the TFI Module 4 times and my truck is still shutting down after running about 20 to 30 minutes. After I let it cool down, it starts and runs fine for another 20 to 30 minutes. This is a common problem for the 1988 Ford F150. No one that I have talked to seems to have a solution. If you have one, I would love to hear from you.
You are appling the dielectric grease to the module before installing it? If not, this will cause the module to get hot and cause it to shut down.
Tester
Agreed about the grease and on the offchance the modules are not failing and that the issue is a lack of spark you should consider the possibility of a failing ignition switch.
When it quits you might probe the coil connector and make sure power is provided in both the RUN and the START positions. (red/green wire?)
If everything fine there then maybe the pick-up coil inside the distributor is failing.
(Hall generator coil or whatever one wants to call it.)
Replace the distributor. The pickup coil is likely failing but requires special tools to replace. Many always replace both parts when either is the apparent cause for the problem.
Next time it quits, check and see that you have fuel pressure and flow to the injectors…It could be a failing fuel pump or debris in the tank…
Yes, applied the dielectric grease.
I was wrong. The rotor,cap and wires were replaced.
It won’t be a fuel problem. Its your ignition. Replace your coil. Its in your distributor cap i think. If not the wire on top of the cap in the center leads to it. This is more than likely your problem.
Is the grease dielectric grease or heat transfer grease? they sure don’t look the same.