just had my 2004 silverado 4.3l swapped out with a 6.0 and all but one cylinder is getting spark. had new heads, intake and cam installed. and installed motor ready to go but looks like one cylinder not getting spark. its got me puzzled. have swapped a coil pack from a cylinder that is getting spark knowing its coil pack is good to the bad cylinder and still no spark. have tried swapping out a whole group of coil packs that work and that same cylinder still has no spark. have tried just swapping spark plug wire still nothing. have tried 3 different computers that did nothing. checked to make sure from the computer to that one coil packs plug makes a circut in the wiring harness and it does so that was ok. just swapped to the wiring harness that came wth motor out for another wiring harness. and that cylinder still has no spark. i dont know what else it could be or where to go from here. any help would be nice so can get back to driving it.