Possible Fuel Leak?

I have a 2000 Tacoma 4x4 single cab with the 2.7L and 5-speed, I got it about a month ago and it has been my daily driver ever since. Every now and then I notice a somewhat strong fuel smell coming from the truck, and I’m not sure if it’s just me but I’ve noticed if I let the truck sit overnight, when I come back out in the morning it looks like my fuel level has gone down slightly on the gauge. No visible leaks anywhere, I’ve looked under the truck and let it sit inside as well and nothing showed up. Not sure if this is an issue or not.

 

Fuel vapor is easy to smell at low concentrations and so even a minor leak can be detectable by nose. If, however, you are noticing an actual drop on your fuel gauge, that's not a minor leak so either you're imagining the change in the gauge or the leaking fuel is evaporating so quickly that you don't see any liquid. If the latter is the case, it's likely that the leaking fuel is hitting something hot, and this is rather dangerous.

The last 2 times I smelled fuel without visible drips it turned out to be caused by a critter chewing a hole in the fuel return line right above the tank. The fuel would drip onto the top of the tank, spread out, and then evaporate. Relatively easy fix once you get the bed out of the way.

 

When you take the gas cap off does it "whoosh" like there is pressure or does it just come off with no sound.

How does it start cold?

 

Haven’t had any issues with pressure in the tank yet, and it cold starts perfectly fine. Been below 10 here recently and it’s never let me down.

 

The truck sat for quite a few years before I bought it, there were some noticeable signs of rodents living in it. I wouldn’t be surprised if they ate the fuel vent line, I have to patch a small hole in the back of the frame so might as well pull the bed and look for that too.