Most of our gas has ethanol in all three grades, occasionally I see a place without. We basically have 87, 89, and 91or 93, and no 94. I did drain the tank, but there's still a bit in there, maybe a gallon or so, but i think I'll dump it and go new. I'm used to using 93 on all my other cars, but that's because they're either turboed (ford escort and Volvo) or tuned a bit (toyota corolla). I guess I'll shop around until I find a place with no ethanol in the mid or high grade, and see what happens.
An interesting puzzle: when I was pumping the fuel out of the tank, via an electric pump, I opened up the gas cap to listen for bubbling letting me know the tank was as empty as I could get it. HISS goes air into the tank, with vacuum. I wasn't sure, so I tried it again, and sure enough, the tank was under a pretty good vacuum, just from the pump sucking out gas. Does this indicate a failed gas cap, that may be causing this? Or maybe a clogged charcoal canister? Does the engine need to be running to create low pressure for the canister to work?
I feel kinda silly not checking the cas cap in the first place. With an oh-so-tasty lip-lock, I was able to suck air through it, but not blow air through it. so theoretically, there should NOT have been vacuum in the tank, yet there was. I made sure to close the cap with 3-4 clicks when closing it, so it should've been venting properly.
On a good note, there was a bit of rusty flakes on the trunk floor, so dropping the tank gives me a chance to clean the area and re-seal it against terminal cancer.
Thanks for the input, guys!