abc15 conducted a study to determine the best brands of fuel for your car, out of a list of 5 nationwide brands. The companies that sell the best unleaded gasoline for your car are Exxon, Shell, and BP. The study involved examining samples of each brand's fuel.
According to autoguide.com, Top Tier unleaded gasoline is the best type for your car's engine. To be considered Top Tier, the gasoline must have a certain percentage of detergent, which is higher than the percentage in non Top Tier fuel. The samples of Exxon, Shell, and BP's unleaded gasoline all had high enough percentages of detergent to be considered Top Tier fuel.