[dcarrb]

"Bad gas" is possible, but it seems after three weeks and a fresh tank you'd be back in the pink by now.

Not to discount any one else's experience, just as a matter of fact, I have for years topped-off my tanks with 87 octane, cheapest stations in town, up to 1/2 tank at a time, including 10% ethanol blends (aren't most?), and have experienced no drivability problems. (Premium here is 93 octane, so a 50/50 regular/premium mix works out to 90 octane, anyway, but it's not like I use graduated beakers to achieve a perfect mix). I don't think fuel quality is the issue here.

Yes, the owner's manual blesses up to 10% ethanol. No to methanol.

dcb