I have a 2002 Ford escap 3l
I’m gettting a p0303 misfire code... I’ve changed the coil pack, spark plug, fuel injector and PCM... and am still getting the p0303 misfire code.

What am I missing?

If that's the only code, try swapping the cyl. #3 fuel injector to another cylinder and see if that helps. Also a compression test would reveal any weak cylinders.

Loose the battery terminal for a few secs to reboot the cpu...the put it back on and drive aroung to see if u get the same code....if u do...the take the fuel injector from the mis cylinder and swap it whit another cylinder injector....if it changes to that cylinder the u know u have a bad injector