: 2001 cadillac deville did not pass smog today for the second time

12-29-10, 12:41 AM
So here is my experience, Took my 2001 caddy with 110k miles to get smogged few days ago and it failed. I made the mistake of not doing any kind of tune up before taking it in. So i gathered parts and replaced spark plugs, air filter, pcv valve, oil and filter. I took it back in today and it failed again.
I ran the on board system diagnosis and no codes are present. Can it be that my o2 sensors need replacement??? the car feels alot smoother after the tune up but im still shocked that It did not pass. (California car)

What do you guys think might be problem??

12-29-10, 01:08 AM
sorry im new and i believe i posted a thread in the wrong section.