1997 Toyota Camry Sluggish uphills / exaust pipe red hot

Last night while coming home.

Car started being very slugglish going up hill almost to the point of stoping.

When we got home the car smelled hot at I opened the hood and saw that the exaust pipe where the oxygen sensor plugs into it was red hot?

the check engin light was also flashing when the problem started.

Any ideas?

Thank you for your help!