Had the car to the dealer today to have the "CEL" checked. Code came up that isolated the purge valve as the problem. The purge valve causes the gas tank to be under some manifold vacuum, so that vapors do not escape from tank, probably through some venting. The purge valve was replaced under warranty. Took 45 mins. "Now what causes this problem?" I asked. The mechanic patiently explained that if the gas cap is not properly replaced the problem can occur. "I don't think that is the problem here, what else?" If the car is not shut off to refuel, it can happen. You know how every gas pump on God's green earth instructs you to turn off the car, well sometimes, when the mercury gets down below 20F, I leave the car running. "Guilty!!!!!!!!!" Moral of story, always turn off car when refueling. It probably says that in the owner's manual, but now that I've heard a good reason, I'll probably be more careful.