Post #1254660

If you are concerned about it, you can mix 5 gallons at a time in your car with the remainder being fresh gas. I.e. if you have a 15 gallon tank, use 10 gallons of new gas with 5 of old. 3 weeks isn't all that long though, its probably fine as long as you didn't leave the cap off. What kind of car is it potentially going in?