I've been reading other post, but still can't figure out my Daughter's car. I've changed plugs, Coil packs, and wires. Drove good for about a week then P0304 comes up again. I have switched plug 4 and 6 around still comes up P0304. Other day I pulled the fuel injectors and switched 4 and 6 on those and still pulls P0304 but it's getting to the part its everyday now. When she goes to start it she says it starts weird and starts shaking specially when she puts in reverse but then when she parks it and I get in the shaking is gone but still has P0304. Just FYI I do clear the code everytime I try something it just keeps coming back. Any suggestions other than what I've done? Thanks