Shift interrurter switch
I have a 1999 maxum 19sr with a 4.3 vortec mercruiser. Awhile back the problem I had was when I reached around 3k rpm it started to rattle and back fire through the throttle body. After checking into it I found that the OHMs going from the interrupter switch were breaking down. To double check I bypassed the switch with a jumper wire took it for a ride and it ran great. So I replaced the switch with a Sierra product. To it for another ride and it ran good no problems for a good while. Coming back into the dock it started having the same symptoms. My question is what would cause those switches to go bad that quick or what should I check? Everything is new coil, ECM, motor, risers and on and on. Could it be an adjustment ?