My MBX-4 runs better on the glo-starter, even after 1/2 a tank of gas. The idle drops alittle and it boggs when it revs up w/o the starter attached. It also has a slight miss about about 80% from max RPM, then it revs up nice and quick the rest of the way. When driving the car on the road it takes 30-40 ydrs befor it reaches max RPM. Do I need a hotter plug or just a needle adjustment?