I had the same problem a few months ago, I replaced plugs, coil, cam sensor, and last not least the PCM. When I would tap on the PCM it would work fine then go to **** again so I figured it was the PCM. Installed a new one and same thing. So I started cuting the covers on all the wiring around the PCM and coil pack and found two wires near the PCM that were shorting out against each other and that was causing it to misfire.
Anyways make sure to check all your wiring before replacing everything. It might save you alot of money.