00 cav 2.2 p0300

Problem car is 00 cav 2.2. I am getting the code p0300 and also the trac off light comes on. Symtoms are missing, stumbling during acceleration, lack of power very black spark plugs. Things I have tried are new plugs, plug wires, cam sensor, crank sensor, good used coil packs. It seems to have real good exhaust pressure and the compression is good. I am going to check fuel pressure later. It seems like there are a few things that can cause this. Does anyone have any tips from what I have done and how to check those things out.