i have a 1994 accord lx, sometimes i get this weird noise sounds like the fuel tank. noise sounds like someone is pulling out a dent and i get this thump sound. best way i can explain it. My assumption is there is air in the fuel tank

 

Sounds like the fuel sloshing around in the tank. You can't possibly fill it all the way without any 'air'.

The top of the tank is uneven, so when the fuel level is just right, there's places where the sloshing fuel can slap against the top of the tank.

 

nah, trust me it's not the fuek sloshing around, this noise is like a pop kinda like when u pull out a dent and the metal retracts making that wobbly sound.

 

I guess I'd get underneath & start pulling & pushing on stuff until I find something loose. Sorry, but noises are pretty tough to figure out over the net.

Another thought...
There's a vent system with charcoal canister. In my '98 it's sorta underneath the left-rear seat. (Dunno where on a '94...) That system provides the only vent; otherwise the gas tank is airtight. If that's screwing up & allowing the tank to pressurize, maybe you're hearing the tank & it's mounting hardware flexing???

edit...
OK here it is. Your EVAP canister is on the firewall, #5. The EVAP purge valve should be on your throttlebody or intake manifold. Is that system OK?

 

thanks for the insight JIM i'll check on it.

 

bump