2002 Chevy Cavalier Code P0130? Help?

Hello forum, wanna say thanks in advance for answering my question..
My Chevy Cavalier (180k miles, 2.2L, 4 door,) recently popped up the check
engine light but I had no mechanical issues and I was out of town (35 minutes)
so I finished my business and rushed home. Poked my head under hood and
found a major problem... Oil Fill/Dipstick cap removed you feel a rush of air and
smells like exhaust but no oil splurts out, just exhaust. Check code on little
scanner and it said P0130- bank 1, sensor 1, oxygen sensor
I'm thinking my piston seals are geating worn but at an exponential rate as I've
checked dipstick at least every 2 weeks and always had oil levels good and no
air flow. Solutions? THANKS FOR ANY HELP
Footnote-car runs great still, no delay in power, no miscolored exhaust, same
mpg, and too avoid blown oil seals I leave Dipstick loose to let excess air vent
(sorry environment)