I recently changed my stock exhaust, and bought Vance and Hines " Big Shots Staggered " for my bike, a 2003 VTX 1800C. I am having fits trying to find the right mapping numbers to make the bike run right, with a Vance and Hines Fuel-Pak. I have a very knowlegeable motocross racing friend who is trying to help me. We thought we had the mapping right, but the bike sat for about a week and a half, while we tried to find time to get together to change the tires. When we were thriugh with all the maintenance, I rode it home, and it was running like crap. It had no throttle response, and the power was there, but it was a "dull " power. Like maybe it had a fouled plug. All the plugs were changed after we had it running fairley good. The Vance and Hines tech's are no help. We have changed the mapping from what they told us because the information did not help. Someone PLEASE HELP!