Wow, answers all over the place. Gas is "good" for about 6 months. Your car and "run on it" maybe even a couple years. I've had poor luck with Stabil and Sea Foam isn't snake oil... old technology, but useful. My advice? change all gas over 6 months

70 Roadrunner convt. street car 440+6, NOS, 4-spd, SS springs '96 Mustang GT convt. street car '04 4.6 SOHC, NOS, auto, lowered "Officer, that button is for short on-ramps"