Originally Posted by SterlingDrive

Try this first and see if this clears up the ECU:

Easy Way to Reset ECU without battery disconnect in G37 - YouTube

Nissan/Infiniti's in general trip the CEL more than any other brand I own. Most of the time in my experiance there is no issues, just need a reset.

If your cat is bad I would go with Berk HFC's, probably the best mod I have done to date.

Good Luck,

Sterling