Sound of gas sloshing around?
 

Is it normal to be able to hear the gas slosh around in the tank so much?

When at a stop with the radio off, I hear it very well.

When shifting into 2nd and letting off the clutch, there is a moderate-volume thud that happens sporadically. Sometimes it sounds like the gas hitting the back of the tank but I can't tell. I am going to fill the tank back up to see if it goes away but I figured I'd ask if this was something normal.

Yup. Side effect of placing the fuel tank under the driver/passenger front seats. Most cars have it under the rear seats. this is what makes the Fit's back seat "magical."

https://www.fitfreak.net/forums/2nd-...-thumping.html

Interesting, I figured the gas tank was pretty damn close. When the tank was full I didn't have a problem. It's about halfway and it's been making the noise. I guess I'll just have to keep 'er filled up!

Anyway, all's well then. Thank you.