I have read some posts about seafoam that claim that it breaks up sludge in gas tanks, and stops up fuel filters, and cleans out injectors. Does it really work like that. I've dropped fuel tanks before and never seen any sludge in them. I live on a farm, and we buy gasoline in bulk (4,000 gals. at a time), so we get all the crud at the bottom of the tank, not to mention that our gasoline pump doesn't have a filter. Having said that, I replaced my fuel filter on my F-150 at 100,000 miles and it was relatively clean. Certianly not stopped up. I guess my question is: What's all this talk about sludge in fuel? Is it really prevelant or are some people getting really poor quality fuel?