All said above ...plus could be your fuel injectors, fuel pump, fuel filter, flush out your radiator...be very sure ur using NGK spark plugs , i use Iridium...beautiful. Ngk wires wouldn't hurt either.

I have a full 3 inch setup...u will lose some, acceleration with an exhaust and intake only. (look where your bottle neck is) Once you have the intake, test pipe, exhaust and headers...you will fill the power from the get go.