I have changed #3 fuel injector, and ignition coil pack, wires, and plugs tested all ohms are good on plugs, plug gap checks out, thinking it could be mechanical at this point. there was oil on the #3 spark plug. Is there a good possibility that the valves are messed up. When I accelerate the car is lacking power and bogs down from time to time. No code has come up since I changed the ignition coil pack today but it is still acting up and I know it is just a matter of time before the code pops up again. Can a mechanical issue trip the computer to throw the misfire code?