Don - try the current OEMs which are Motorcraft/Autolite. Federal-Mogul who now owns Champion evidently does not make the same quality plug they used to years ago when I would ONLY run them in any vehicle. The Ford truck site folks dislike the current Champions, and my last few encounters with then in anything Ford have been less then satisfactory(my 'long gone 'bucket and my last 2 p/u trucks).