Tire Valve problems of the 2003 Saturn ION

The contact owns a 2003 Saturn Ion. The vehicle has firestone Infiniti tires, size 195/60r15 (na). On three isolated events, within a five week period, the valve stem on the tires failed. The tires lost pressure overnight on two occasions. During the most recent failure, while driving 55 mph, the tire lost complete pressure and the contact nearly lost control of the vehicle. He still has possession of one of the tires. The dealer stated that they would not be responsible because they were not the manufacturers. The failure and current mileages were 48,000. Updated 07/15/08 updated7/15/08.