Can a malfunctioning oxygen sensor cause a rich or lean fuel mixture?

Sep 25, 2015 ... Cylinders 2-5 looked normal. What could cause the end plugs to foul? My thought was those plugs stay cooler, and not hot enough to burn off ... Feb 28, 2014 ... Years ago I thought a plug fouled was because of the carbon and lead build up. ... cause of sparkplug fouling is oil getting into combustion ... Apr 8, 2004 ... the plugs are dry black "coated" the engine begins to miss, can take spark plug wires off and no noticable change in idle acceleceraton. the egr ... Causes of Carbon Fouling: · Continuous low-speed driving and/or short trips · Spark plug heat range too cold · Air-fuel mixture too rich · Reduced compression and ... Aug 18, 2001 ... Rich mixture and or rich main jets can cause the carbon/plug problem but if its really bad enough to cause a problem you should see black smoke. Jun 2, 2021 ... Could it be that an excessively rich idle mixture causes carbon fouling, then the lack of spark allows oil to accumulate? I just want to be ... Apr 12, 2013 ... ... cause the plug tip temperatures to decrease and carbon deposits to accumulate, possibly causing fouling and misfires). A solution to this ... ... spark plug because the exhaust smelled quite rich. The plug (original Bosch WR7 DDC4 with two earth points) was heavily fouled with carbon. I cleaned it up ... Sep 4, 2011 ... I say this as the plugs on the wife's R80 also look a little carbon fouled. ... plug causing the fouling. A leak down test would help ... May 13, 2021 ... Carbon fouling on a spark plug is caused by a problem with the fuel that you use. Often, we describe it as a fuel mixture that's too rich, which ...