It turns out the front face of the tank is pushed in from some long ago damage. It's been patched with some type of weld, mostly around the fuel line. I found a pin-hole leak at the front bottom corner, which I patched with a fuel tank putty. Problem solved, or so I thought. I jacked up the backend to take the wheels off and didn't it start leaking (much worse) at a higher spot! More putty, have to jack it again to see if it's finally sealed.
