My sons 2002 blaster is spittn and sputtern, thought it may have been a fouled plug, replaced that and no change, when you give it throttle and get into the higher rpm range it spits and sputters and jerks. I also pulled the carb and cleaned that thouroughly, with no change. I run 93 octane at a 32 to 1 fuel ratio, I am just baffled at what it could be. Any ideas would be a great help thanks in advance.