Trouble codes

code: po 303 and po 304 cylinder misfire detected on cylinder 3 and 4.

The history involves replacing the coil pack, spark plug wires and spark plugs. I am still having the trouble code and engine skip.

It is probably time to move to a fuel delivery problem. How you do that depends on the kind of FI you have, but a shop manual will likely be in order.

But before that I would suggest just checking the compression to rule out some kind of mechanical issue.