I've seen coill packs 4,6, and 5 with the O2's plugs in em, the #6 injector mixed up with the acc plug, and check the tps sensor too. If the harness checks out than check the fuel pressure, it should be around 45 with key on car off and around 38 with the car running. If the fuel pressure checks out pull the plugs, and while the plugs are out do a compression test.