i dont know on that specific van but i can give u my general knowldege if you can get under there and see the gas tank there may be a valve you can open other than that i would take the gas line off and open the gas cap. I just did this as I was changing the fuel pump. There is no drain valve, but simply get under the car, disconnect the fillerneck hose where it enters the gas tank (it's attached with a hose clamp), then use a hose and a pump to drain the tank. It's easier to do it this way as you won't have to fight the kinks and bends in the filler neck when trying to get the hose in.
standard was 22 but Chevy had an optional 33 gallon tank
25 OR 33 WAS OPTIONAL I think it's a 33 gallon, but I'm not entirely sure.
yes
In the fuel tank.
Not sure about a 1992, but a 1993 G20 fuel pump is definitely in the tank. It's an electric, turbine-type in tank design. My understanding is the 1991-1994 are all the same.
Order one from a GM dealer
You need to lower the fuel tank to get at it.
In the gas tank. You need to take the tank down since it's on the top of the tank.
Read your owner's manual.
It is in the throttle body.
The fuel relay on a 1992 Chevy G20 5.7 liter, 350 is under the hood attached to the firewall at the top, just under the wind screen
inside the gas tank and it comes out the top.