Your truck s computer controlled engine management system will "light" the check engine light and store a fault code for the Oxygen sensor when there is a problem. This may occur if the fuel mixture is too lean or too rich and beyond the adjustment limits of the computer. For example, a vacuum leak or plugged fuel filter may cause a lean condition. Excess fuel pressure from a failed fuel pressure regulator would result in a rich condition. Check and correct any of these or similar problems, i.E. Leaking intake manifold gaskets, severely plugged air filter, incorrect location of vacuum lines. The oxygen sensors maybe okay.
Wednesday, February 2nd, 2011 AT 8:16 PM