Misfiring. Need Help!
Ok Guys, Here goes;
2002 vtx 1800C. 73,000 miles, bought it new. K&N air filter and Roadhouse Shorty exhaust installed 70,000 miles ago. Other than that, the motor is completely stock. Never had a single problem with the bike.... until now. Took it out for a short ride the other day and after about 5 miles it started missing really badly, backfiring and bucking like a wild horse. Got it home and replaced the stock iridium plugs with Bosch 4419's. (stock "deep" plugs had some fouling.) Took it out for about 15 miles. Same problem. Shut it off and restarted it and it ran fine all the way home. Back out for another 5 miles, same thing again. Back home, used induction timing light to check each wire. Every one showed an intermittent miss at mid to high rpm. Never has flashed a code on the FI light. Here's what i've done so far:
Inspected plug wires for breaks.
Trimmed ends of plug wires and reinserted them into coils.
Ground fix mods were done in 2003. Did them again.
Unplugged and sprayed contact cleaner on all connections under the seat, side panels and left engine cover. (Chrome one below the ignition key).
Installed new battery.
Rode 1/2 mile and it started missing again.
Ideas? Bad coils?(could both go bad at the same time?) Bad ECM?