1992 Lexus LS 400 Catalytic converters GLOWING RED

Yester I was parked waiting on my daughter to get out of school when my lexus started to smoke real bad. I was parked with the car running when I notice the engine start to stumble just a little bit. Then about 5 minutes later smoke started to come out from underneath the car. I got out and look underneath and saw that the catalytic converter on the drivers side was glowing red. I looked at the passengers side and it was glowing red too! I shut it off so it could cool down. After 30 minutes I drove it home and as soon as I started to drive I noticed it had lost some power. When I got home (about a 5minute drive) it was smoking and sure enough both catalytic converters where glowing red again.

What could cause this?

Exhaust restriction?

Bad O2 sensors?

Thanks!