Tough CEL problem.

My buddy has a 99 GSR. Whenever he drives it really hard (red-lining etc.) the check engine light will come on. At that point it tends to run like crap. His air/fuel gauge will read rich instead of bouncing back and forth like normal, even though it's just a crappy autometer. The idle also raises up and the car just doesn't run well. It runs like this until he turns the car off and restarts it. How can he make this go away? He has i/h/e, and a vafc. Thanks for any help you can give. Btw, he's throwing:

P1298 - Manaf air/fuel meeting

P0108B - Map/Baro Circuit Highlight