I need to know if, anyone has experianced a P0306. have changed all plugs, wires, coil pack, injector, ran comp. test. all check good. put an inline spark tester, in place, clear code and drive it for about 10miles, then spark fades , which trips the P0306? put diffrent coil on and same thing. I can read schematics, but cant find at local Ford tech. library. any sugestions?

 

Welcome to the forum. I'm going to move this to the 4.2L forum in hopes that you will get more info. I am wondering if it may be a harness issue. You might try some contact cleaner on the coil primary plug.