Your 1995 Cadillac Deville running rich means that too much fuel is getting
into the combustion chambers, and it more then likely has to do with the
oxygen sensors. A smog check repair station will have to find out why your
Cadillac Deville is running rich and probably producing high CO. The
diagnosis for this fault should begin with inspection of the fuel injection
"feedback" system. This includes ensuring the oxygen sensor is working
properly, your Cadillac's emissions computer is receiving the signals from
the oxygen sensor, the computer is computing the data properly and sending
the correct signals to the fuel injectors to either increase or decrease
fuel delivery to the combustion chambers. At the end of the feedback test it
will be know whether the high CO fault is electronic or mechanical, and the
technician can further diagnose the fault.
Your Cadillac Deville's smog check failure diagnosis should also include
inspecting for high fuel pressure, air restrictions (i.e. dirty air filter)
and leaking fuel injectors. A dirty air filter may restrict ample air from
entering the combustion chambers. Any condition which could cause a lack of
air getting to your Deville's intake manifold will create a rich fuel
condition and result in high CO.
