My catalytic converter has been rattling horribly recently, and throwing codes... so I figure I should get it replaced for my California registration which is due in a few weeks, and smog is due this year.

Looking up aftermarket cats on the official California site yielded no results for 1999:

https://ssl.arb.ca.gov/PartsSearchTo...earchTool.aspx

I then called the ARB to ask them what was wrong with their system. I was told categorically that if a vehicle model year isn't listed then the manufacturer never certified that year for aftermarket cats. She said if I had further inquiries on the matter, I'd have to bring it up with the manufacturer. She said installing an OEM cat was the only option, legally, for my VX.

I'm pretty sure it's a data error in their system since the vehicles are identical with the exception of tire size I think, there's no reason I can think of that Isuzu would certify 2000-2002 and not 1999, given the vehicles are identical. I don't know where to contact Isuzu to find out why 1999 isn't certified, their website is more or less scrubbed of any non-commercial vehicle stuff.

So, my question is, what recourse do I have? I doubt that fighting the ARB is going to yeild much. I could install a cat certified for 2000, but I think they check the cat type upon smogging to make sure it matches the database, and the smog place is in big trouble if it doesn't match.

Has anyone else gone through this? If so, what did you do? Can I even find an OEM cat? Is it legal to install a used one? Is it possible to contact someone at Isuzu with queries about why 1999 is not listed? If so, who would that be?