first thing is what station did you buy from.... im in houston as well.

food for thought gasoline is formed from petroluem distillate only the vapor burns from emitted gasoline liquid once its reached its vapor point it will no longer become a vapor temp and baro pressure regulate this. the liquid left behind will be an oily residue. this is not the proper way to detect contaminated fuel. the only way is to send off a sample to a testing facility and let them do a knock test and chemical breakdown...