P0300 Chevrolet -04 silverado w/5.3

Question

when code comes on the left bank spark plugs get sooty n black, sometimes lite will go out on its own. truck will run fine again. what could I check, changed plus n wires fuel pressure hold psi at all rpm

Answer 1

Hi there,

Since this is only occuring on one bank I would suspect the issue to be with the front O2 senosr on that bank. I would start there because that would control the fuel mixture to the specific bank.