How Long Until Gas Goes Bad?

[Foppa]

My P5 has been sitting for about 5 months or more. Within that period of time it has only been driven about 5 times or so, less than a mile each time.

I've heard that gas can go bad after a couple of months.. Is that true?

If so, is there something I can add to the tank to prevent any damage? Or should I just replace the gas before using it again?

 

[mech81]

From what I've heard, the fuel octane deteriorates with time making the fuel more prone to pre-detonation (knocking and pinging) especially if its an engine that requires premium. The solution to this would be to put in a fuel octane booster. Sometimes if the fuel is especially from a "dodgy" source you can get sedimentation + film (similar if you leave stagnant water in a box) - that one I'm not so sure how to rectify. I'm not sure how to figure out one from another though. Maybe try the octance booster and see if it helps.

Hope that points u in the right direction.

ADDITION:
Actually just have a read here and i've learnt something myself
http://autos.aol.com/article/does-gas-go-bad/

 

[Foppa]

Thanks for the info and link!