[gotcha6]

I'm new here, but I think I've stumbled onto part of the problem(s) with the old distributors. My '96 5.7 truck was breaking rotors and scoring caps. Replaced both, and still had a misfire. Took out the old distributor and found a lot of end play in the shaft. Seems a gasket/spacer between the top and bottom halves of the distributor had deteriorated. Since the local parts houses were closed I improvised and installed an o-ring into the assembly to take up the slack. As for my theory about what was happening:
1. The end play caused the distributor shaft to thrust upwards when decelerating and push the rotor into the cap. 2. It also caused the Hall Effect sensor to misread the notch in the rotor.
I realize my fix is only temporary, as most Buna-n o-rings aren't compatible with detergents in engine oil, but thank to the links & suggestions above, I'll be ordering a billet distributor shortly.
Looking forward to learning how to keep the truck going here. It's just getting broken in @ 257k miles.

 

[gotcha6]

Got that billet distributor in this weekend. It comes with a different retaining clip that doesn't allow the distributor to rotate like the old one. Unbeknownst to me, my old one was out of sync, so a pull out/drop in produced a hard start, but it ran enough to get me to work. Once there, I decided it needed to be corrected. Used the old retainer & kept moving the shaft 1 gear at a time. Couldn't get it right until I tried this trick:
This engine doesn't have a timing dial, so I unscrewed the #1 spark plug. Using a zip tie as a feeler gauge in the spark plug hole I turned the engine with the crankshaft balancer bolt until the zip tie was caught between the piston & head, then backed off just enough to get the zip tie out. With #1 being TDC, it is either in fire or exhaust mode. I then took off the cap & reset the rotor to the #6 terminal as it was closest to the position I had it in. A few rotations on the starter to align the oil pump shaft & make the housing drop in place and it purrs like a kitten.......