ok heres whats goin on, my car starts, idles, runs fine. however, when i am in 5th gear just cruising at normal throttle say at around 1300-1500 RPM, and say i want to give it some more gas to pass a car, i push the pedal, not full throttle, but just a bit more gas and the car willl miss, i can feel it jumping through the stick and the car shakes, what could this be? one of my buddies suggested a spark plug, what do you guys think?? thanks!