Plug question?

[ajb2006]

I'm trying to find answers for my coworker, he has a 07 convertible and is going through plugs. He had the car almost 4 years now and just put a 3rd set of plugs in. He uses the car only for fun, trips and hitting the town. He never pushes the car, he just likes driving with the top down. I think he said he only put 20,000 miles on it in 4 years. He uses the right fuel and keeps up on the maintenance but what would cause the plugs to foul out so quickly?

[Rudolph320i]

likely the car is almost never at operating temp for very long, low speed putting isnt exactly what these were designed for.