1996 Chevy Silverado Miss firing cyl. #6

Have you checked compression on #6?

James has a good idea. Check the compression. However, compression can be OK and you could still have a broken valve spring, broken rocker arm, etc. If one of the valves will NOT open, the cylinder will not fire. If it's the INTAKE valve, no fuel/air can get into the cylinder. If it's the exhaust valve not opening, the burned mixture cannot escape therefore contaminating the new mixture entering the combustion chamber. Long story short. Check the valve train on that cylinder. Don't forget about the FUEL INJECTOR. If it's not firing, there's no fuel to that cylinder. If it's throttle body injected, never mind. If it's multi-port injected, check the third injector from the front on the passenger side. You can even swap it with, say, number 2 (front injector on pass. Side) and see if your code reader indicates number 2 now. Like I said, if it's throttle body injected, never mind. I can't remember what year they got away from that.