Hello, I have a 1986 f150 with a 5.0 efi paired to a c6. Runs really well except at random stops when it’s warmed up for example a stop sign or red light, it will bog in drive and maybe even stall. Never did it all winter in harsh Canadian weather but as soon as summer hit it started. I have replaced the distributior cap, rotor, plug wires, coil, spark plugs, in-line fuel pump, fuel filter, fuel pressure regulator, tested the iac and egr, I have no intake gasket leaks, no vacuum leaks, and good fuel pressure. Still it does it, it’s pretty annoying. I am starting to think it’s the ecu because it is so odd, no problem on the highway at all. Only when the engine warms up and I’m driving in the city. The computer’s part number is E6TF-12A650-K1A. Rockauto.com has a remanufactured one but the number is E6TF-12A650-KA. One number difference, can I get away with that one? Any input is appreciated, or if you have any other ideas. Thanks

 

Well the truck is never going to be anything close to collectable and is 33 years old (8 years since it became an antique). I'd haul it in for salvage value and move on as parts are going to be increasingly difficult to locate as time goes by.
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There’s no way I’m doing that lol, the thing is like new. 45000 miles. It’s a lariat too. That’s why I’m putting the effort into it

 

You’ve done the things I normally think of doing.
Could it be bad gas? Has this condition been prevalent for more than a single tank of fuel?

if all else fails....have a mechanic look at it.

 

Thanks for your input, I have went through lots of tanks of fuel in typical 5.0 fashion, Been going on for a few months now, symptoms are the exact same as when it started. Do you think there is a chance it’s the ecu?

 

'86 is just before the capacitor plague that causes problems in later gas Ford trucks (generally '88-93), but it wouldn't hurt to look inside for this:


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Replacing parts is NOT diagnosis, and new parts are generally NOT as good as originals. Unless a part fails a published diagnostic test, or is due on the maintenance schedule, leave it alone. If you don't have a Haynes shop manual, it's time to get one:


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Once you have it, read it cover-to-cover at least once so you know what's in it & where to find things. Same for a digital multimeter & its operator manual:


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Then start TESTING things - not replacing them, unless they fail the test. When you get a replacement, TEST it - it must pass the same test that the previous part failed. If not, it's either just as bad, or you did the tests wrong. This caption lists most of the sensors & actuators:


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You'll need a special gauge to measure fuel pressure:


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A compression test is a good way to get a general idea of an engine's overall condition:


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This site may also interest you:
http://www.garysgaragemahal.com/