i know there's been plenty of discussion on the best octane to use 87, 89,91 ... I agree with the use FRESH 87 high quality gas. My question is are the big guys like Chevron, Shell, Exxon any better than say a Citgo or a Diamond Shamrock? I swear that my truck runs better on Shell or Chevron gas, but it may just be perception. I'd rather run the cleanest burning fuel I can get. Also, you see fuel being delivered to Brand name stations by all sorts of no-name trucks ... Is all gas the same really? Do they put additives in at the plant or when it's delivered at the station?