What engine, and how many miles are on it? Is the same plug fouling or just misfiring? An oil-burning engine will foul plugs faster than anything. You can buy spark plug extenders for $2-3/ea., but that is a temporary fix. They work, but they also lower your compression in that cylinder.
Low voltage produces misfire, too. How long are you idling before the misfires? Does it straighten itself out after running high rpm's for a while? We need more info. - Dave
Royal Oak, Michigan (Four miles north of Detroit, and 12 miles NORTH of Windsor, Canada). That's right, we're north of Canada.Ford 292 Y-Block major overhaul by simplyconnected