Rendy - I don't believe that the catalytic converter would be involved in high hydrocarbons. If the O2 sensor has failed, the fuel injection defaults to a rich condition to avoid damage from detonation. Also, if the frequency valve fails, the same is true. Or, you could have a cold start valve gone mad, and dumping fuel at all times. High hydrocarbons indicate an overly rich mixture, so fuel system failures or misadjustments would be where to start. Another possible source could be simply that your car needs a tune up, with fresh plugs, wires, cap, etc. If you have a cylinder that isn't firing consistently, the unburned fuel will result in high apparent hydrocarbons. Any other thoughts from the rest of you? Toby Peterson VIN 2248 Winged1 --- In dmcnews@xxxx, Rendy Cheng <rpcheng@xxxx> wrote: > Yesterday, my Delorean failed the smog check due to high hydrocarbon. The technician played the rpm little bit but it did not lower the hydrocarbon.