Walmart used to carry a test kit that measured the alcohol content of gas. Test when you get it and test when you use it. E85 isn't always E85. It picks up water very easily from the air and there is always condensation to worry about. There are kits available no ebay too. Just buy the better quality kits. If water is the problem buy some 190% alcohol (Pharmaco) from a booze store and add it in or try a product like HEAT. Your just trying to dilute the water with anhydrous(water free) alcohol.