I have a 99 GSR. I can't get my check engine light off. I did a diagnostic test and I keep getting a code 67. Code 67 is: catalyst system efficiency below threshold. I thought it ment it was stopped up. So i took it off and gutted it clean as a whistle and put it back on. I reset the computer and drove the car about a 100 miles. The check engine light came right on. I don't know if it is where the front o2 is reading the same as the rear o2 senser. Any advice would be appreciated. Thanks.

 

get a new catalytic converter. they can not be cleaned. that code means the chemical reaction that is supposed to be happening inside the cc is not happening the way it should. JUst get a high flow cat and be done with it. also another option if you just want to turn off the check engine light is too remove the rear 02 sensor. zip tie it to outside air and just plug the 02 bung in the cat and reset the light. wont give you anymore problems after that. any questions pm me.