ZZP 3" catted DP = Service engine soon light... Why??

I installed a new ZZP 3" catted dp a couple weeks ago and all has been fine until a few days ago when the service engine soon light came on. I reset the computer, because I never did upon installing the new dp and all was fine for a few more days, when all of the sudden the light came back on today. I went to autozone to have them scan my codes, and two codes, both depicting catalytic converter inefficient malfunction blah blah came up. Is this a regular occurance with a hi-flow cat on the L67 engine, or could there be a defect with my new cat? The car was fine for two weeks with the new dp on, and now it is pulling these codes.

Yep. Hi-flow cats can do that.

Get an O2 Emulator from ZZP

...that's what I was thinking

same that should fix the problem

Read the portion under "IMPORTANT information concerning High Flow Catalytic converters"

https://www.zzperformance.com/grand_prix/products1.php?id=551&catid=110

Thanks guys. I feel better about it now haha. I'm getting an overkill pcm soon enough, so I will just have the code removed. I will not damage anything from driving with the code stored in the pcm, correct? I don't mind seeing the SES light for the time being... My car still drives the same and I don't have emissions until April

nope, no side effects except for the light, you'll be fine

Did you have the rear o2 sensor put back on? 01+ grand prixes have been known to go into "retarded mode" without the rear o2, due to entering a cat test mode which floods the engine with fuel. If you haven't noticed a difference in your car, you're probably fine, but something to keep in mind.

See this thread: http://www.grandprixforums.net/f65/removing-rear-o2-sensor-01-newer-7092.html

High flow cats have been known to trip the SES light for cat efficiency.

Yes, the rear 02 is still installed.

same thing happened to mine after installing the hi-flow cat...I added the O2 sim and no more lights.