a friend and i were thinking about making some biofuel instead of paying $3. 30 a gallon. read a few threads about how its runs ok and won't gunk your engine and a few on how the 3rd gen trucks don't like it and it thrashes the fuelsystem/injectors and valves. so has anyone been running biofuel (not b5 or b20) for a few thousand miles and then taken the head off to check valves and pistons and all the nice moving parts inside? if you make your own how much of a pain in the hiny is it? does it have any kind of shelf life? after the upfront cost of the kit and getting started if you can only run half and half/half bio then fill with #2 its gonna take awhile to recoupe the cost, is it actually worth it?