i almost had the chance to dig into one of the same exact machines with the exact same problem, about 3 days before i could get my hands on it, the dood totaled it. I cant help ya at all, but i can tell ya that the wreck WAS NOT problem related.
If i personally had to go after it, id be checking the Gear Selector Switch and wiring first.
If i personally had to go after it, id be checking the Gear Selector Switch and wiring first.