Hawke I doubt if this is your problem but I'll throw it out as something to consider as a last resort. On an old Ford Festiva (Yeah, I used to be that poor) the engine quit one cold January night. After 5-10 minutes it would restart, run for a couple of miles, then die again. Repeat. Repeat. Repeat. Finally got home. After a very frustrating search,it turned out to be the engine control module dying. When it was cold it worked, when it got warm it didn't. Replaced the ECU, no more problem.
By the way, ont the white powder residue you found on the strainer - I've had a white residue precipitate from old gasoline after long storage. Your problem may have started as bad (old) gas. Next time you have your tank apart, take a scotchbrite pad & go over the inside surface. (One of my hobbies is old tractors - you'd be amazed at what happens to gasoline over time) Bill
