5.7 GXI -E no fire on # 2,3,7

I have a 5.7 GXI -E and not getting any spark from the distributor on # 2, 3, 7 need help. Any suggestions or ideas as to why? The cap, wires, rotor, and plugs are all new.

I've been talking to a shop forman and come to find out that they have been having a lot of problems with the distributor caps as of late so i changed mine out again ( now mine is almost new it has about an hour on it most of which is trying to figure out what is wrong with it ). and now all the cylinders are firing. So beware also if your having a fuel problem like to much pressure (anything above 50 is to much) there is a filter on the return line that goes back to the fuel pump it gets clogged. clean that screen and it should take care of it. Gonna take it out tomorrow to see if works

Took the boat out today and still was missing out (# 7 wasn't firing) not as bad but still missing took the plugs out checked them switched them around rewired it boat ran like a top don't understand what happened but knock on wood its working. Still gonna get an extra set of plugs and wires just in case