did you put fuel stabilizer in it ? does it smell like varnish ? If you did put fuel saver in it and it doesn't sell like varnish, and it still smells fresh.
I had about 10 gallons that was in my bass boat when I got it it my was still good, I put min in my truck a couple gallons at a time, until gone .. truck seemed to run better lol .. my truck is a old 95 model .. I dont know how it would effect a newer vehicle.
If its varnish smelling , you can dispose of it at the hazardous waste dump on amnicola hwy in Chattanooga, its open like the second sat of the month I think call the city and ask them to be sure, or its really great for starting brush pile fires if its really old , dosent burn real fast like fresh gas.. acts more like kerosene when really old