My college student drives a 2001 Mazda Tribute with a 3.0 L engine. We replaced the battery in October 2012,( after not starting on 3 different occasions) but last week her car won’t start after a week of no driving. AAA jumped the battery and I drove it home to my mechanic which is a 90 minute drive. He let it sit for 3 days without running to see what would happen-it started with no problem. We had the alternator removed and tested and the results were fine.
The airbag check light stays on when the vehicle is running, other than that nothing seems to have been left on to drain the battery.
Have your mechanic (or one that is closer) perform a parasitic draw test. I will assume that airbag light is off when you turn off the car?