I have a hyundai iload 2011. Is there a plug at the base of the gas tank to drain fuel?

SOURCE: Contaminated fuel

most gas tanks don't have a drain plug.can eith try siphoning it out with a hose called a magic siphoning hose or disconnect the fuel line and put the line in a container to catch the bad gas.

other option is to drop the fuel tank and empty

SOURCE: 1999 Olds Alero, unleaded gas. Am having problem with gas tank

have your evaporative purge valve solenoid check. because its controls the gas vapors going to canister purge or vent valve.take it to dealers have the evap system scan because its not venting or controling gas vapor.it suppose vent gas vapor to intake to be burn.if it dont work it causes excess gas vapor pressure built up in tank. make it hard to pump gas into it.

SOURCE: Unleaded Fuel in a Diesel Engine

THERE is 2 ways to do it 1 take the tank out and drain it OR get a small 12volt pump as they fitted to a lot of English cars (Morris Minor Jag ) etc and fit a small fuel pipe 3/16" to both in let and out let and put the one with arrow to tank into tank and other end to a fuel drum (about same size as tank)and plug into 12v battery and let tank pump dry,

When you refill tank with Diesel add 1 ltr of petrol to full tank of Diesel it starts and runs 30% better.

If your dad tried to start it on petrol then undo INJECTOR pipes and spin over till Diesel comes out before you tighten injectors feed and starting engine.

Testimonial: "Quite helpful, think we might take the tank completly out, but whats the easiest way?"

SOURCE: I need to drain the gas tank on my 2002 dodge

Hopefully your not attempting to replace a fuel pump in this vehicle or the tank its self?

There is no drain plug you have to purchase a fuel extractor pump. They are manual or electric. You put pump hose in tank threw fill up and start pumping the fuel out into its container.
CAUTION; WEAR EYE AND BREATHING PROTECTION. KEEP FIRE EXTINGUISHER'S HANDY.

SOURCE: Unleaded gas in a diesel fuel tank

do not worry about draining it, pour about 6 to 8 ounces of engine oil in it, and top it up with fresh fuel, it will be fine. The only way to drain the tank is to remove it and turn it over.