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My 5.0 liter 302 starts and runs good EXCEPT it stalls occasionally in different situations. Sometimes at idle, sometimes at highway speed and sometimes in town driving around. I coast to a stop, turn the key back to the detente position, then it starts up right away no problem. I never lose battery so I know it's not that. I replaced the fuel filter and it runs better but still stalls. I'm thinking of replacing plugs, rotor and distributor cap next. Also ran fuel system cleaner through it as well as fuel injector cleaner. Even tried premium gas to see if higher octane would help. Anyone else have any ideas?
Someone mentioned something similar recently. It could be the TFI ignition module overheating. It's screwed to the distributor, and can get hot enough to cause damage. The quick fix is to replace it, hoping the new one will last longer. I relocated the one in my 87 Mustang to head off potential problems:
I do Love the FTE forum and now feel even less alone!
I have an 86 F-150/ 5.0 EFI with EXACTLY the same symptoms, in the same driving situations that you describe. (had it since new and 167,000 mi)
I am one of those "limp it along" till the last minute, DIY 'fools"
Thanks for asking the question to the Forum. Thanks also to You who provide the info in the informative replies.
As I am now searching for direction with another situation to solve, being down to the last limp will start with fuel filter and go from there.
May be back with more questions and/ or let you know what solves this one.
Thanks again
I've been working with a local garage to diagnose the problem. We think it might be the fuel relay which is a quick fix. That's what we're replacing next. If it isn't that, we will try the fuel pump that is downstream of the two gas tanks. I guess my model has three pumps: One in each tank and a third outside of both tanks. Since the issue happens whether I'm on the front or the back tank, we know it can't be the pumps inside the tanks.
Problem solved! We replaced the fuel relay switch and it has been running without a problem for about five days. Simple, inexpensive fix. Of course, there were some hours I had to pay for to get the diagnosis. One piece of advice I can give everyone: If you research the problem yourself and troubleshoot it as far as you can before you bring the car to the garage, it saves them time. I had it narrowed down enough that they only had to check a few things. That switch was second on my list to check. While it was in the shop I had them replace the upper and lower ball joints, thermostat, flush and refill the coolant, tighten up the transmission lines and check the brakes, so Old Blue is runnin' better now.
OK. I've replaced the fuel filter, fuel relay, ignition module and a sticky EGR valve, plus replaced a cracked plug. It ran great for a week and then the stalling happened again. Thinking maybe the computer next? Any ideas anyone?