more time tonight. i went back and read and saw a pic of eng. comp. at minimum you need ground strap from cyl.head to fire wall, a hard wired body ground wire [8ga.] is really needed.[clean surface].[ battery neg.to body sheet metal.] everything else is searching for ground path except starter motor. otherwise how does it get there? thru trans shift linkage? throttle cable? don't know if this is your condition, but above must be certain. it will cause flickering at any time. just trying to help rpmagoo.