Done deal: the floats in both tanks were drowned at the bottom of the tank. Easy fix with junk yard parts - thanks to no salt and sunny California, no seized, rusted bolts! The MPG thing still concerns me though - seems it must be able to do better than 11-13mpg at 55-60 on the freeway with a totally empty van. It has a high top on it, but it looks very aerodynamic the way it slopes back. No idea what the gearing is - any idea how to tell? And any way to improve it for better mileage? I don't care about power, I'd rather show up at my destination late without friction burn on my wallet.