Update
car on lift and everything is solid, clean and sealed. No rust no broken wires no leaks.

Truth is , i don't think the wideband lied. It actually told me something about the gas being sold from a popular car wash chain, delta sonic
I ran that tank to empty and re filled twice at the same Sunoco. The gauge is reading like it was before this issue - completely normal.
NEVER have I seen this before and I have had gas from all over here to ohio - no issues ( BP, mobile, crosbys...)

Seem like they might be using a bit more than E10 in those 93 pumps...