2004 F-150 5.4 engine
The engine 84k miles, developed a severe miss. I replaced the spark plugs and boots and the fuel filter. Still missed. Took it to ford dealer, the service writer said the #4 coil was bad and that the plugs needed change. I told him that I changed the plugs and boots. He said that if I did not use motorcraft plugs that my truck would never run right. I thought all after market products would do the same job. Am I right or is the guy blowing smoke? I went home and replaced the #4 coil. Road tested it and my OBDll came up with P0304 code #4 cyl miss. Has anyone out there had any similar problem? If yes what was the solution? Please Help!!!