So I have a 1999 scrambler 500 4x4 and whenever I give it throttle it starts to big down and when I let it off it dies. Its getting spark and fuel. I replaced the fuel pump. The petcock, the carb, fuel lines, fuel filter. And for electrical I've replaced everything but the rev limiter. I took the srv to get it worked on and the guy set the jets and everything on the carb to where it should be and still no luck. The contacts on the ECM are also not touching. Any help would be greatly appreciated. Thanks