My van was running great. My van has two gas tanks, one of which I never use and is rusty and gross. I accidentally switched gas tanks and ran my van for 20 minutes with really dirty gross gas. I switched back to the regular gas tank. Now my van runs hard, smells, and the exhaust is dark. It runs, but it stinks.
what do you think? Carb rebuild? Bad gasket leaking oil? How much will this cost? Thanks.
There is definitely bad gas in your carb now but you probably have fouled your spark plugs. I would change them and try to flush out the carb. You shouldn't really have to spend more than a few hundred bucks, depending if the carb needs a rebuild now. I would also see about having the second tank either removed or at least disabled so you don't run into the same situation again