Question: how do you know if you need to replace your gas tank?
Answer: Corrosion. It can be difficult to detect, but corrosion inside the gas tank, which may include rust, can cause your car to run poorly. ... 
Dented or damaged. A dinged or dented gas tank may cause damage to the fuel pump or fuel pump mountings as well. ... 
Leaks. ... 
Gasoline smells.