It's a good thing that most of my patron's are patient, because I get a few requests per week that take over five minutes to track down.
This time, it was about a news program he just saw. He knew it was on a specific channel. He knew it was about some kind of gas that voids a vehicle's warranty. But he wanted to know more.
So I did some sleuthing. It took me a few minutes, but I found an article that was about just that topic.
Apparently using ethanol in certain vehicles (basically, every type but Ford & GM) can void the warranty if any damage happens due to using ethanol in the vehicle. According to the article, it accelerates wear and tear on the engine.
It was an interesting article (linked to just above), and the patron thought so too.
As a side note to the use of ethanol: I tried it in my car, but my MPG went down drastically. I did some sleuthing of my own and found that unless the price of ethanol is at least 25% below the price of regular, it's actually more expensive to use ethanol than it is to use regular.