The '97 454's were terrible on fouling out plugs. They changed the carburator on the '98 model and that helped the problem somewhat. If you don't let the Cat warm up properly before you start riding, or you start the cat, drive down to the mailbox, and come back and trun it off before it's warmed up it will definitely shorten the life of your plugs. When the spark plug fouls out you will not get it started. I know from experience. I sold my '97 and '98 454's to my mother and stepfather and my little brother is constantly fouling out the plug on the '97 model because he'll run it for 5 minutes and turn it off. I suppose it's just the nature of the beast. I don't know how the 2000 Cat will behave because I haven't had it long enough.