Pulling the tank wasn't too hard with the engine out. I followed Richard Atwell's DIY Fuel Tank Restore thread. I was shocked at the amount of rats nest hiding out behind the firewall after pulling it off.
As I looked closer, and while holding my nose, I saw the skull of the culprit!
It turns out it wasn't only the skull; it was the entire skeletal system from skull to tail and toes included! Oh man, did it smell. Pee and poop coated the bottom of the tank bay and I am still spraying it down and scrubbing it out. I can't get the piss smell out of my nose...
The tank itself looked pretty good, dirty, but no noticeable holes.
I wonder what rat hair and pee/shit does in regard to resistance drop? My gas gauge never did work below the half way mark...maybe I know why now (pic of the sending unit).
I opted to go the full kit rather then follow Atwell's mueratic acid route.
I am planning to prep the tank and apply the POR-15 this weekend.