[asshanson]

The gooey stuff is somewhat common for running e85. I ran for over a year once without checking them and one clogged it had so much junk on it. A minute or two in an ounce of gasoline clears it right up.

I'm guessing the rear o2 is disabled since it's only for emissions, but it shouldn't be throwing any rear o2 codes if that is the case.

Good luck figuring things out.