I'am having a problem with a 93 Ford Taurus 3.0L ffv That has high co2,The test spec is 12.00 in az and it is at 12.91,I have 45 for hc and 1.20 for nox so they are ok.I have replaced plugs ,cleaned maf wires ,changed oil,checked for leaks,timing,Drove 50 mile... Login to read more.