Just got 06 Scion tC auto and it sucks gas I put $20 in today and white maybe the total of 30 miles altogether and I'm back down to like nothing .... help!

Doing tune up tmrw plugs n air filter

 

There's really no way you can have this engine get 3mpg. I would check ASAP for a serious fuel leak.

 

I had that happen on my old mustang once. The rubber grommet from the filler neck to tank rotted away and every time I would take a hard corner gas would dump out. Anyway unless the car is running really bad I would think you are leaking somewhere. Even if an injector was stuck open that would probably just hydrolock and bend the rod... Start smelling for leaks.