Yep,had to replace mine two weeks ago. Minding my own business, diving down the street. Next thing I know, I'm coastin to the curb. Coil was only 2 yrs. old. I don't know if being a 60K coil has anything to do w/ longivity. I don't think so, but it 's the first HO coil I've run.

 

I haven't had a chance to swap out the coil but the truck is running much better. It hasn't been a week yet but no stalling so far. My second theory and logic of why the truck was stalling is as follows. The truck ran great until the TFI died. I replaced it and the idle was a little rough but I didn't think much of it. The outside air temp at the time was relatively high. The truck started stalling on a cold damp morning which made me pull out the distributor and attempt to install a new pickup coil. When I failed and reinstalled the distributor the truck ran and idled a little better but still stalled when cold and damp. When I ran the tests in the Haynes manual all of the tests were grounding to the distributor itself as well as a test of continuity between the distributor and the block. Since I had to take the distributor out for some of the test I cleaned off all of the dirt/oil and wire wheeled the tab that holds the distributor in place. My thoughts are that the coefficient of thermal expansion of the two metals allowed the distributor to shrink when the temps dropped. There wasn't sufficient enough ground so the truck would idle rough and die. Since the distributor expands more than the iron block, the ground was restored shortly after the engine warmed up. Now the clamp provides constant ground and the dielectric grease will keep moisture at bay. It's just a thought... I'll keep you informed if the truck stalls or continues to run great.

Edit:
Well if it sounds too good to be true it probably is... Not even ten minutes after typing this I went to start the truck and it stalled again. It took 20 seconds of cranking before it finally kicked off again... Bummer, looks like I'm buying a coil today!

 

........................I don't know where to start, so I won't. But when any of my coils have died (only two) they stayed dead regardless of all attempts to intimidate or resuscitate!

 

I don't want to jinks it but I found a know issue on a Ford TSB. It stated that higher octane fuels can cause the engine to run in a lead mode which causes my symptoms. The solution is to run out the higher octane fuel and refuel with 87 octane per the manufacuters specs. I should have thought about that seeing as how the issues started shortly after switching from 87 to 89 octane... We'll see if it makes a difference...

 

I don't think that little difference in octane would shut the truck down. Unless you're already running way lean to begin with. Totally different vehicle type, but I had a camry that the coil went bad on. It died in traffic a few times during a week long period, replaced the cap and rotor button and that seemed to help for a day or so, then it completely died and wouldn't start again. Towed it to a shop and they replaced the entire distributor, that wasn't it. Turned out to be the ignition coil, and that sounds very similar to what's happening to you.

 

Yep! Get a can of "SEAFOAM" and pour it into the brake booster Vac hose w/ engine at idle & at norm.op.temp.https://www.f150forum.com/f72/how-seafoam-eighth-gen-f150-1987-1991-a-31505/ This will get rid of any combustion chamber build up you've developed during your higher octane misadventure! Don't feel to bad, alot of people make this mistake. The higher octanes are only for engines w/ higher rates of compression. The only way your stock engine would qualify is a fairly drastic advance of your base timing. Like maybe 16 or 18BTDC! The higher the octane, the more controlled the detonation. 87 octane actually has the highest overall combustion properties! Google it.

 

Same thing on my 1995 F150...It would turn over and over but wouldn't start...pulled the coil wire from the distribitor..no spark...it was the ignigtion control module...
Jay