I store 5 gallons of gas in the carriage house as added backup for my generator. About every 6 months, I pour it into my pickup and buy fresh. I put Stabil into the fuel when I buy it in containers.
If the fuel causes any trouble just mixing it in, just buy some Chevron Techron and put it in the tank where you put the fuel. Alternatively, just use good name brand fuel. When I bought my 2005 Tacoma, I think the fuel injectors were fouled from (probably) use of non-major-brand gasoline. It only got 22 mpg on the highway. Gradually, it has risen from 22 to 23.5 to 24ish to now 27ish and may higher on this tankful (went 160 miles on 1st quarter tank; higest before was 150). Steady use of Exxon regular has cleaned out the injectors. It has power now at 32 mph in 4th and 42 mph in 5th. When I first bought it, the thing was gutless until at least 35 and 45 respectively. Major brand fuel suppliers have to pass BMW's very stringent fuel system cleanliness test at 100k miles (essentially NO deposits).
This is a 4cyl, acess cab, 2wd Tacoma. The old 1996 averaged 27.4 mpg over 90k miles. They're both rated 26 mpg EPA highway. This newer one is 300 # heavier but has direct injection and a viscous fan.
Ralph