What happens if you cross your fuel lines?

[jstang209]

im trying to figure out why my gas milage is so bad.. only thing i havent done yet was replace my fuel filter.. its not that old neways.. But my car is an x 4 banger and it still has the fuel line comming up on the driver side.. so i was wondering what would happen if i accidently crossed them.. and made the return line connect to the sending line, going up to the intake??

 

[speadfreak]

I'm pretty sure that they are two different sizes.

 

[jstang209]

ok.. thanks but not really what i was looking for

 

[95cobradude]

the car wouldn't run and they are 2 different sizes.