My concern today is about the percentage of ethanol added to gasoline, up to 10% Ethanol Content is what most gas pumps display, and have for a number of years. The latest, which I've heard on the radio, is that the ethanol content may be as high as 15% by this Summer. My pickup truck is an '02 Chevy Silverado 1500, ten years old, and I always thought that the "up to 10% ethanol" gasoline wasn't a big deal for a vehicle built within the last decade; every 2-3 tankfuls (34-gallon tank, never gets below 1/4), I add a can of "Sea Foam" to treat the gas. I also have 47,000 miles on the truck, drive it 3-4 times a week and only when I can justify using it, and keep it in my garage when not using it. A talk show host I was listening to this morning said that the ethanol was especially bad for older vehicles and older engines (not that I consider 10 years to be "old"), and that ethanol gas was just bad in general. One of the callers to the show said that having a vehicle sit too long with 10% ethanol gas could cause seals to dry out; I'm wondering now if I'm giving my truck enough "exercise" by limiting my usage of it to 3-4 times a week, and should I open the garage and let the engine run for a few minutes on the days I don't use the truck for transportation? I like this truck and I intend to keep it for a long time, so I don't want anything on it to go bad any time soon, especially with only 47,000 miles on it. It gets maintained on a regular basis, with oil changes and grease jobs twice a year, and I check the fluid levels every week, topping off as necessary. The truck has been running great so far, and I want to keep it that way. Any comments/advice on how often to run it, and about modern 10%-ethanol gasoline are welcome.