The results showed that on average, Top Tier gasoline had 19 times fewer carbon deposits on injectors, intake valves, and in the combustion chamber when compared to regular gasoline. Consumer Reports - June 7, 2015 Location and price drive gasoline sales, according to a new survey by the American Automobile Association. But an extensive study also conducted by AAA, reveals that consumers would be wise to factor the quality of the gasoline in their purchase decision. Using an independent engine testing lab that specializes in fuel analysis, AAA sought to answer the question: Is “Top Tier” gasoline worth the price? The short answer is yes What Is Top Tier Gas? Gasoline is essentially a shared commodity, often stored in common containers until it is purchased by a major retailer. After that, the retailer treats the gas with a specific additive, thereby giving the fuel its brand identity. But are these additives just a dosage of marketing hype? Top Tier gasoline was developed in 2004 to go beyond the minimum standard for detergent additives to better protect increasingly sophisticated engines from carbon buildup and deposits on the intake valves—which can result in a rough idle, acceleration hesitation, knocking/pinging, and reduced fuel economy. Over the past 20 years, engines have become far more precise, operating under tighter tolerances and at higher compression ratios, while targeting cleaner emissions and improved fuel economy. To achieve these goals, eight automakers—Audi, BMW, Fiat Chrysler Automobiles, General Motors, Honda, Mercedes-Benz, Toyota, and Volkswagen—have united in support of Top Tier gas, specifically recommending it to their owners with the goal of preserving their engines’ original performance and emissions over time. List of Top Tier brands linked in story. Read More: Top Tier Gasoline has lower deposits.