..untreated gas has a storage life of about one year...it loses some octane rating but will still work satisfactorily...add fresh hi-test asap...follow with quality injection cleaner(prevents varnish build up on injectors)and you should be okay...gas is a commodity, like any other..it gets stored for market advantage...some of your fresh gas at bargain prices is simply "below flash" gas...pretty much what you have in your tank right now...'97 2.8 bg