Good Morning, I have a misfire problem, and i replaced the spark plugs, wire set, cap and rotor and the fuel injectors, and the van still have it the same miss fire in the cyl 5, what else can be?

 

Ignition coils, crankshaft sensor, fuel pressure. Did you scan for trouble codes?

 

Could be the poppet valve on that cylinder. Not a great system anyway. If you dont want to tear into the top of your motor right away, try a good fuel system cleaner, or have it done at a shop. If its not spark, then fuel. Also make sure you used iridium plugs, and did not try to re gap them....they are not meant to be gapped or adjusted.