<This is from original question poster> After following the advise on this forum, I have replace the O2 sensor, spark plugs, spark plug wires, Dis cap, dis rotor. Earlier today, I had my car smog check again.. Guess what? It failed the test again. Result from the test are following : HC (ppm) Max allow:150 My car: 111, CO (%) Max allow:1.50 My car: 0.54 CO2 (%) Max allow:NA My car: 13.8 O2 (%) Max allow:NA My car: 1.1 RPM 2466 So... for high RPM, it is okay. The following values are from idle case. HC (ppm) Max allow:120 My car: 241 (too high) CO (%) Max allow:1.50 My car: 0.67 CO2 (%) Max allow:NA My car: 13.4 O2 (%) Max allow:NA My car: 1.5 RPM 734 Other than catalytic converter, what else can be the cause of this.. Thanks every one! rendy #4220 > Hi > > 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. > The technician has suggested me replace the catalytic converter. I > thought the catalytic converter support to last forever. There is no leak > on my exhaust system. My car does idle a little low around 600 rpm. I > also notice a little less power from the engine and higher fuel consumption > in recent months. My car is approaching 30k miles and still has the > original O2 sensor. Does any one has idea what else I can do before I > replace the catalytic converter? > > I would like to thank everyone in advance. > > Rendy #4220