O2 sensor CEL after DE day
 

I ran my first DE track day yesterday - what a blast to really see what these cars can do! Car ran well during the event (other than cooking the old brake fluid - lesson learned, change the brake fluid before the next DE!)

While driving the 2 hours home, after about 90 minutes of highway driving, I hit stop and go traffic and got a CEL light.

I checked the fault codes this morning and they were all O2 sensor issues. I reset them and the codes have not come back (yet).

Any ideas of what would cause the CEL in the first place?

Thx-

Depends upon what codes you observed.

I had the same thing happen a couple years ago. I ran it hard on Nürburgring and then flew it home at constantly over 100 mph for 1.5 hours. At the 1st stop sign, a CEL popped for an O2 sensor. Reset it and it stayed off for about a year until my MAF sensor took a poop on me.

Codes were:
P1602
P1123 - code 27, lean
P1125 - code 35, lean
P1130 - code 34, lean
P1128 - code 26, enrich
P1276 - code 22, below low limit
P0159 - code 23

Year and model of the car?

1997 boxster with 2.5l tip, w/under drive pulley and low temp thermostat - rest is stock for now.