With timing light on lower, leading. plug wire the timing is dead on the leading mark. Switch to trailing, top, wire and timing stays on proper trailing mark but randomly jumps to the leading mark.
I swapped leading/trailing wires from cap to coils. No change. Swapped leading/trailing wires from cap to plugs. No change. Anyone seen this before? Cross triggering?

 

welcome to the board.

i can't say i'm very well-read on the subject, but i have seen J9fd3s post about wire orientation a number of times. i think he said they should be 90° in orientation (relative to leading) or you can get crossfire, which may be what you're experiencing. if he sees this, he'll probably chime in and explain it better.

 

Thx. I did some searching. Found one of his explanations and suggestions:

(1) DO keep the wires as far apart from one another as possible; (2) DON'T route the wires perfectly parallel and close to one another; (3) If #2 can't be avoided, then have the parallel wires cross one another at a perpendicular (or close to it) angle once or twice along the run.

Will get out and rip off those pretty plug wire spacers/separators and do some rerouting. See if it makes a difference