I have a 1991 Ford F250, 5.8L that is 2WD and has 126,000 miles on it. Purchased this truck about 3 years ago (really good price). I did not have the time or need to get it repaired and did not want to deal with ridiculous CA SMOG regulations. When I purchased it the check engine light was on. I did some troubleshooting and replaced the fuel filter, idle air control valve and throttle position sensor. This took care of the CEL. I then tried to have it SMOG’d and it failed because it was smoking (valve cover leaks). In July I purchased valve cover gaskets, plugs, wires, cap and rotor to clean things up and make it run better. It passed SMOG test in September and my son started driving it.
It ran well for about two months. One day my son was driving to work and the truck stalled (in neighborhood) and would not restart. I pushed it out of the road and went back to get it home a couple of days later. It started immediately, I drove it home (1\2 mile) and switched the fuel tanks a couple of times without issue.
I hooked it up to my tester and it produced a code 67 for a neutral position switch problem. We replaced that and it started and drove great for a couple of days. Then it happened again. Driving around the neighborhood it stalled and would not start again. It took a few days to get back to it and again once it was started it drove home fine (again, only about 1\8 mile). We again hooked up the tester to the truck and it returned a Code 11 (All Clear).
I am thinking it is a fuel issue of some kind. The truck sat for a while (three years) so I am wondering if there might some junk in the fuel tank(s) that could be clogging things up. I don’t think there is a pump problem because it does run after it sits for a couple of days. Appreciate any help you can give.
You can test it when it won’t start to see what the engine is not getting. I would put my money on a NO Spark issue. A quick spray of starting fluid in the air filter when it won’t start is a quick and easy test. If the engine runs on the starting fluid you know it is a fuel related problem. If it does not then you know it is an electrical issue.
I am guessing electrical issue because it is pretty common for what you are describing. It starts and runs fine when cold but once it warms, the engine dies. Leave it set long enough to cool down and the engine starts back up and runs. This is exactly what happens when the Ignition Control Module starts to fail. The part is fairly inexpensive and easy enough to change out yourself. The replacement instructions taken from the manual (see below) indicate you need to remove the distributor, but in most cases this does not need to be done.
Ignition Control Module
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Ignition Control Module Replacement
- Remove the distributor cap from the distributor, and set it aside (spark plug wires still connected).
- Disconnect the harness connector.
- Remove the distributor.
- Remove the TFI module retaining screws.
Step 5 must be followed EXACTLY; failure to do so will result in damage to the distributor module connector pins.
- To disengage the TFI module’s terminals from the distributor base connector, pull the right side of the module down the distributor mounting flange and then back up. Carefully pull the module toward the flange and away from the distributor.
- Coat the TFI module baseplate with a thin layer of silicone grease (FD7AZ–19A331–A or its equivalent).
- Place the TFI module on the distributor base mounting flange. Position the module assembly toward the distributor bowl and carefully engage the distributor connector pins. Install and torque the two TFI module retaining screws to 9–16 inch lbs.
- Install the distributor assembly.
- Install the distributor cap and check the engine timing.