Wait until the car has half a tank, throw it in there. At worst, the car will not run as well as you might be used to. Common case: you won't notice the differe

Wait until the car has half a tank, throw it in there. At worst, the car will not run as well as you might be used to. Common case: you won't notice the difference. Your car will be far more tolerant of old gas than your mower or weed trimmer.