I installed my SLp shorties and this code has been there ever since and can't get it to drop. It is also accompanied by a P0430 code but i think its because of the 400 code. Anybody have any ideas on how to get them off gotta pass emissions this month!! thanks

 

P0400 = EGR system, low delta MAP detected.

This one sets when the PCM cycles the EGR valve and doesn't see the expected change in MAP pressure. Do you still have the EGR system functional? If so it can be the result of reduced EGR flow due to the lower backpressure in your new exhaust system. If you no longer have the EGR system working, the PCM has figured that out

P0430 = Bank 2 catalytic converter low oxygen storage.

This indicates that the passenger side after-cat O2 sensor is not detecting O2 levels consistant with a healthy, functioning catalytic converter. If you still have the cat in place, its either a deceased cat or a failing after-cat O2 sensor. Swap the after-cat O2 sensors side-to-side and see if the problem follows the sensor (faulty sensor) or stays where it was (faulty cat). If you have deleted the cat and have O2 "sims", the sim is not working. If you have deleted the cat and don't have sims, the PCM has nabbed you