Lyric discussion by lovenightandrock 

Cover art for Gasoline lyrics by Airborne Toxic Event, The

I agree that it is about THE girl. He is clearly with a new women now "And she'll step away". But he still thinks about the girl. They dated when they were 17. And then there was a chance at 21, probably to move in together or get married but he left. He thought it was too serious and the commitment scared him (maybe she got pregnant or was ready to get more serious) "I wasn't having any fun And the words you said Tore through my head" And he wishes he showed up and told her to get into the car, but he didn't. Everything else has just been an imitation and he can't move on cause her memory burns "like gasoline".

I think we all have stories that we can relate too. It is really an awesome song.