Have had my 2005 Toyota Tundra Doublecab SR5 4 weeks now, on several occasions have had to raise the drivers seat back up to the level at which I like it and it seems to lower by itself overnight. I checked with the Toyota dealer about this and they have heard of this from one of their own employees which owns one and could not come up with a cause or no logical reason other than when you get out your leg hits the lever and the seat is lowered then. But it seams to be more drastic than just one movement of the lever, I must pump it up approx. 10 times to get it back into position. I may remove lever to see if this helps. Otherwise love the truck! Twice as good as my last two z71 Silverado Crewcabs!