i have a gt5 skyhawk with pc high compresion head, sbp exhaust, jaguar ignition jnx header port billeet intake and a nt carb. it starts fine runs find and is able to get up to top speed for a couple minutes and then it sputters and wont hardley get above an idle and wont rev back up pls help. keeps foul'n plugs and im runin a 40 to 1 ratio . pls help