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What is wrong?  anyone else experience this?  I can not afford to [pay for several items changed and still a problem   it like to shut off at lights but not all the time  it feels like it is coughing   i keep ver up to date with oil changes and belts and  tune-ups  etc please help jackie 305-934-5274

 

keywords: cadillac deville, cadillac, new cadillac's 

Oxygen sensors or O2 sensor ( there are 3 of them ), mass air flow sensor or MAF sensor, temperature sensor, catalytic converter can all cause the engine to run lean. The fuel systems on all newer vehicles are controlled by the computer. Before the computer can decide how to set the fuel supply, it must first determine the temperature and amount of air coming through the MAF. If the air is cold the computer richens up the fuel mixture acting as the choke. As the temperature rises, the mixture leans out.  After the engine burns the fuel, the O2 sensors determine the amount of unburnt fuel in the exhaust gasses before and after the catalytic converter. If the amount of fuel unburned in the exhaust gases is above  a certain limit, the O2 sensors tell the computer which in turn makes adjustments. If the Catalyst is failing or plugged, the final exit O2 sensor will alert the system also.