wolfpackjeeper
NAXJA Forum User
- Location
- 500' and 500KCAS, RAF lakenheath
I'm no expert, but did have an expert tell me once that the 4.0 can be sensitive to plugs. He's had lots of folks come in with runability issues...changed the plugs to the original stock Autolite plugs and problems go away. I've run them in my '89 4.0 without problems...and that's 270,000 miles. They aren't spendy either...bonus!
stock is not autolite, it is champion. At least from 86-97, maybe the new ones switched. Th OE plug is a champion copper RC12cy something or another plug. The autolites do work fine though