Last week I was able to change the radiator from my 1994 GMC Safari in which now it is cooling down, my next thing that I noticed is that my engine is running a bit rough in where I accelerate and the car wants to kinda shut off. My question is can it be the spark plugs? Can it be the coil? the wires to the coil? or everything together? THis happens only when I want to push the pedal to metal or accelerate in the freeways. Anyone can help me?