One day my father and I went to remove my shorty headers from my '03 Silverado. When we went to put them back on we believe we nicked the third spark plug on the driver's side. The truck did not register misfire (yet) but sounded off and lagged when I would get on it on the highway going back to college. I replaced the spark plug we believe I hit but when going to my AFROTC class the check engine light came on (flashing) aka misfire. The next day I replace that plug again, replaced the 4th plug on the driver's side and cleaned the 2nd plug on the driver's side. No problems until today when I opened it up a bit. I'm think maybe a hurt a wire from the constant on and off. If it happens again I'm think replace every plug on the driver's side and the wires too. My plugs are E3's and the wires are Beldon from NAPA. Anyone have any thoughts?