97 chevy pickup 350 half ton

97 chevy pickup 350 the computer says number 6 cylinder is miss firing. replaced all plugs wires and cap and rotor
 

What do you mean by "check" them?
 

i replaced plugs, wires, and cap and rotor.
Well looks like you took care of the easy stuff.....I'm guessing you're still getting the P0306?

Those did have problems with their injectors but at this point it might not be a bad idea to take a check compression reading. Also check for vaccum leaks.