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When it stalls, try to determine if it is due to lack of spark or lack of fuel. It sounds like an ignition problem, but I suppose it could be something like a fuel tank (sock) filter clogging and then allowing some fuel to pass after sitting. Once you narrow the field (ignition or fuel) it should get easier to diagnose.
I wonder if we can still purchase the ignition module from Ford oem ?
I have not had good luck with aftermarket (Napa), and bought a new one (duraspark module) which promptly went south. yep.
So i take it in to Napa, and before they would replace as faulty, they 'checked' it on their module checking gismo.
Ha, of course it checked fine, so no replacement. Yep, i chucked it in the dumpster and went to Ford and ordered the motorcraft module, and Bingo, no more stalling. _ _ _ thank you Napa, the shiester's.
Be thankful our older pickups don't have a "roll-over safe oil-pressure switch" to deal with going south. ha
Modules can fail, and after setting for a bit (cool-down?) will "reset" themselves and appear to be O.K. Almost universally, continued use will result in another failure.
I have seen some blue grommet Motorcraft modules for sale.
Last edited by Ozzie H.; Aug 22, 2021 at 09:53 AM.
Reason: added information
this happened to me.. bought a 78 4x4 351m from the original owner. truck had been sitting for quite some time. truck needed a lot, rebuilt carb, tune-up, fuel pump, new gas tank, calipers etc, etc. got it running great, thought i would run the cheaper ethanol gas (new tank and all). truck ran fine for awhile then started laying down on me, stalling. would sit and idle all day. long story short, the last thing i checked was the new fuel pump, bought a replacement pump. when i removed the pump luckily i looked into the hose inlet, sure enough it was plugged with a gel like substance (couldn't keep the float bowl full enough to run at speed). the inside of the gas tank filler hose had deteriorated.
cleaned pump inlet, replaced filler hose, cleaned out the tank and stopped running ethanol, truck has performed almost flawlessly for years now.
All of the above are good ideas of where to look. One thing I noticed on my non-evap 77 F150 351M, was that after driving a while, it would start to exhibit some weird signs. Was a gas station putting fuel in it, and when I removed the fuel cap, it sucked a bunch of air into the tank, which led me to believe the fuel cap is not venting like it is supposed to. I left the cap on loosely and it has never done it since. I also haven't replaced the fuel cap yet