gonna be a generic post, cause I still need to find out specifics, but a friend of mine bought a late 90's civic, had exchaust work done, stock mind you, and then it starting throwing check engine light, later found out it was a california car and had 49 state exhaust system installed not knowing so, is there anyway to work around this without out changing exhaust system again, he's located in NJ where inspection is extremely hard to get around

 

Then the answer would be no. But if California is the 50th state, with NJ being counted among those other 49, why would it be a problem in New Jersey?

 

the cat converter is Ka, 49 st, the car is a Kl, california car, so it throws a check engine light because of the mis-match, trying to figure out if the is a way to trick computer that everything is copacetic

 

New info for me. I'm still going to stick with my original answer and say no.