''There seems no easy answer to the simple questions: What is bad gas? How can I avoid it?'' [xfloat=right]http://www.cleanmpg.com/photos/data/501/Shell_Station_3_059_regular_unleaded.jpg[/xfloat]Road Warrior - Morning Call - Mar. 3, 2008 Shell is a Top Tier and if you can find it at the lowest cost, do it. I guess -- Ed. Q: Recently you said there was no difference between Shell, Exxon, and other gasoline brands. In fact, there is a big difference. Shell V-Power is a Top Tier product. It has four times the additives to keep the throttle body and fuel injectors cleaner. Bob Kalb, Salisbury Township Your recent story on the cheapest gasoline rings true. Of course, there are claims made by the auto makers that not all gasoline is created equally. Please check out Top Tier gasoline for another perspective on the supposed quality differences between brands. In your opinion, is Top Tier really the top, and if not, what allows certain manufacturers to use such labeling? Barry Coles, Bethlehem A: Also hammering the Warrior's cylinder head regarding gas quality is Jason J. Gaydos of Bethlehem, who contends that low-cost, low-detergent fuels clearly reduce mileage and harm engine components. In the Dec. 24 column, the Warrior said he could find no reason to refrain from buying no-name gas. The objections came in faster than a Porsche 911, prompting another run at this volatile issue. It turned out to be a long trip, with few rest stops offering clear answers. It's hard to distinguish the marketing emissions from the clean air of proven facts. The Environmental Protection Agency requires all gasoline sold in the United States to meet minimum specifications for chemical additives that act as detergents to help keep fuel injectors clean and internal engine parts free of carbon deposits and other impurities that could impair the engine's functioning, and thus increase emissions… [rm]http://www.mcall.com/news/local/all-warrior-mar3-08,0,6880132.column[/rm] Thank for the find Fr. John!