Sounds like a weak cat. I had the same issue with my REDCAR and when the turbo started to blow oil, it killed the cat but I did not realize it and had the hardest time passing smog last year.

I tried EVERY trick in the book almost but the guy said "your cat is probably just bad, go down the street to this place and for $110 he'll put a new one on"

I came back an hr later and it passed with flying colors!! <img src="/forums/images/graemlins/lol.gif" alt="" />

I know.. Cali smog sucks!! <img src="/forums/images/graemlins/nana.gif" alt="" />

1986 SWB Turbo Pajero (aka RedCar). 2" Lift, 33" BFG ATs, Rear locker,Custom 160a Alt, 9000lbs Warn Winch,Con-Ferr Custom built Conferr rack just for RedCar!, Safari Snorkel,3 AGM Deep cycles

1995 SR (Lucky)-SOLD..Kinda sad

Nissan Leaf(Astro), Tesla-S 85kw (Nicoli) & 2014 Rav4EV (Tesla inside)