Really Strong Gasoline Smell
 

I was out on some trails yesterday, and I was having a problem with a really strong gasoline smell from my 4runner the whole time.

I first noticed it on some easy dirt roads about 30 minutes after leaving pavement (any 2WD car could make it). I was parked checking a map, and it smelled a little like gas in the car. After few minutes more driving I got out to see if I could find the source, and the smell was really strong. It mostly smelled near the gas filler area, and a bit behind the car. There was no smell under the hood, under the car, or from the tailpipe (with the car off). And turning the engine off didn't stop the smell. I tried opening and re-tightening the gas cap, but that didn't help.

I was at probably around 10,000 feet (and live at 5,000 feet) if it matters. Maybe the pressure in the gas tank was high relative to outside? But opening and closing the gas cap should have equalized it.

I had the check engine light for "very small evap leak" maybe a year ago, and I replaced the gas cap then. There were no check engine lights yesterday or today, and I went for a short drive today and didn't smell anything. I haven't noticed any leaks or unexpected loss of fuel.

Could my problem be similar to this thread?
Code P0456 - When its not the gas cap

If possible go check your Long Term Fuel Trims and Short Term Fuel Trims via a live read on a code reader and if they are pretty high like in the 20's on LTFT then it is probably a P0174 or P0171

I don't think it's coming from the exhaust. The smell is just as bad when the car is off.

Have u check the bottom of the fuel neck?
The fuel neck to the tank has a rubber gasket.
When it wears out the fumes come out.
Have u replace the fuel filter?
If u have check it. If u haven’t it might need one.

I used to think that the most difficult thing was to get rid of the smell of gas from my hands. But then I found out about an effective way. Wash your hands with vinegar to suppress the fetid smell. When you wash your hands with vinegar, it is not necessary to rub them against each other. Just spray your hands with a small amount of the product and wait for them to dry naturally. After that, you can rinse your hands with soap and water if you want to suppress the smell of vinegar. There are actually a lot more options, but for me personally, this is the best one.

A common cause for gas smell like that is the fuel pump hard lines rusting out.
The pump sits in a recess on the top of the tank. Water collects there and the metal lines of the pump rust.

The fuel pump housing, tank, and lines coming off the tank are all plastic on 4th gens and almost all mid-2000's Toyotas and up. I suppose it could be possible for the frame mounted lines between the tank and the engine to be rusted out, but I feel like that'd be a noticeable issue (fuel physically leaking on the ground).

To the OP, have you inspected the EVAP Canister for cracks/damage and the vapor lines? I'd be a little shocked that it didn't set any DTCs yet, but that would be my guess as to noticeable fumes. Another thing would be to check the fuel line connections at the engine (driver's side area of the engine bay behind the fuse block) and see if those are leaking. Sometimes people jam them on wrong when they're doing an EFI service or other work and it can wrinkle the plastic coating on the lines and cause a poor seal that drips fuel.