My truck is bone stock except for 265/75 tires and a replacement k & n air filter. It is driven like a grandma would on highway and town roads. New plugs Ford plugs 20,000km ago, new fuel and air filter 5,000km ago. No check engine light, no driveabilty problems at all? But I have a bud at the local Ford dealer so maybe I can get him to scan it anyways.