My Dad's 94 Z28 has developed a problem while driving in 6th gear. It seems to miss or lose power somewhere caseu on hills where it woul dnormally make it up no problem, it bucks fro a instant before he downshifts to 5th. Is thsi a ignition problem, be it Opti or possible plugs and wires? If so, how long does it take to change plugs and wires on a LT1? I know it certainly isn't a 20 minute deal, thanks guys