It is very common to smell gas fumes after letting a Miata sit for a while. It usually happens when the gas tank is more full. This can be caused by a couple of things, but what seemed to fix my problem was cleaning out the check valve. This is located on the top of the gas tank behind the seats. When functioning properly the ball inside the valve should move freely. It can get gummed up over time not allowing the ball to move freely and causing fumes to leak out!
We made a video to show you how to access this check valve. I tackled the issue while I was replacing the top as the rear carpeting was already removed!
2 replies on “How To Fix Gas Smell In A Mazda MX-5 Miata”
How do you get to the check valve without taking off the top? Is it as easy as pealing back the carpet?
Yes, you do not need to remove the top to access the check valve. I was replacing the top at the time so it seemed like an opportune moment.