poured water into gas tank insted of gas

Drain the tank, fill with fresh fuel, replace, flush the fuel system and replace the fuel filter. And take friend off car borrower list...

oops. That happened to me many years ago, my then 4 year old stuck a garden hose in my 1984 Audi Quattro, If a gallon or two got in there, you must drain the tank completely, take the fuel line off the engine end, pressurize the tank with air and purge what you can,then open the test nipple in the fuel rail and pressurize the system again and get as much as possible out. Put is some gas, and and alcohol based water remover additive. You can drain the tank by taking the fuel line off of it. When it gets running, run it for quite a while, like a half hour, go take a drive. The fill it up with gas and drive some more. If this does not work, make your friend foot the mechanic's bill, and do not delay. Change filter too.

We were typing at the same time Lars..you beat me to the punch but your answer is better than mine,,to the point

And really, that's what happens loaning your car, especially if he or she was too cheap to put gas in it before driving around

I always make sure the tank is full when someone borrows any of my cars, deal is that it is refuelled when I get it back or the person in question gets the bill for fuel plus a bit for my time. Saves me a lot of surprises that way.

That will work. personally there are a few things I never ever loan. Car, gun. wife. The wife you can have

Your friend is too stupid to live much less drive