well as you know i currently have nothing behind my 2-1 pipe since i snapped the cat bolts from the 2-1 to the cat trying to install my hi flow and when i was driving down the highway last night i punched it to pass someone and it threw up a cel. it ran fine for the rest of my trip and when i stopped it idled fine and my accelertaion was normal, when i shut it off i let it sit for a little bit and started it back up and the cel was gone and didnt come back

this is an OBD1 car and the sensor is in that 2-1 pipe so the sensor is getting the exhaust, what do you think might have caused this cel?

also i havent driven very much since i snapped the bolts, maybe 60 miles