[aerodave]

The only issue I have with TOP TIER is that it's not an exhaustive list of all gasolines that are good for your car. It's a list of retailers who have ponied up the cash to the automakers to get on the list. Exxon/Mobil claim that they exceed the detergent standards for TOP TIER, but don't care to be a part of the program because it's gimmicky. I can't blame them. How many people—even owners of cars whose makers recomment TOP TIER—have ever heard of the standard? If the customer recongition and demand is not there, you can't blame an oil company for deciding it's not worth the price of admission. If enough people started going to the Shell across the street because that's what their owner's manual told them to do, you can guarantee that Exxon/Mobil would certify their gasoline in a heartbeat.