I PUNCHED MY CAT ON MY 2000 GSR AND NOW MY CAR IS GETTING A ENGINE CHECK LIGHT ---CODE 67---THE MANUAL SAYS (Catalyst System Efficiency System below threshold, bad catalytic converter)...IT COMES ON WHEN I GO ABOUT 80MPH ON THE FREEWAY...DOES ANYONE KNOW HOW TO FIX THE PROBLEM.

 

Maybe you damaged your o2 sensor.

 

You won't get this problem with OBD1 vehicles. However, with OBDII vehicles, there are two O2 sensor. The first one reads a value before the catalytic conv., the second one read a value after the cat., then the ECU compares the two values, if they are the same or very close (as in your as since there was no cat to change the emission gas), the ECU will flash a code.

 

Delsolvtec: Gee, you punched out your cat and now the ecu says your cat is bad.
I wonder why???

Rawdigga: Hollow cat wont cause drivablilty problems. You have something else
going on.

Code 67 is just a light letting you know that the cat is not working. It doesnt cause
any problems, just shows you a light.