Spare Tire problems of the 1999 Ford Mustang

The spare tire in the trunk of the vehicle h blew up. The vehicle would not start because the tire caused the trip wire to shut off the fuel. After consumer's husband pushed a reset button the vehicle started. The vehicle was a convertible. The convertible top was pulled back on the left side by the explosion, and the trunk lid was pushed. Before there was a rattling noise in the trunk and the consumer took the tire out. After cleaning the trunk out she put the tire back in, and had not used it. A week later it blew out. The consumer had the vehicle since may 2005. She was unsure if it was used by the previous owner. The consumer has not changed anything in the trunk area since this happened.