My tire pressure light came on yesterday morning. When I took my car in for the recall inspection I had them check the tires. They said the tires were all fine, probably just lower because of the cooler weather. Apparently the light indicator is pretty sensitive, warning you if the pressure drops even 2-3 psi. He said next time I come in for an oil change have them refill the tires with pure nitrogen and that will reduce the weather-induced pressure variation. Considering air is already 80% would 100% nitrogen really make a difference? Or is this just a money-making scam (although he didn't say if they charged for the service or not, but I'd imagine they do since it's not a warranty issue). Anyone have 100% nitrogen filled tires?