2012 2500 hd ltz 6.0L gas 187,000
Had some bad gas thankfully only 7gals but
added seafoam to try and clean it out I originally got obd codes for misfires and too lean but after running 2 tanks of gas through I'm consistently getting a too rich error codes. I have a logey start in the morning and a little engine chatter before the engine warms up. I ran the engine at idle and revved up the engine to 2500 rpm when I let off the gas my short term fuel trim jumped out of range to +19.5 for a moment and fell back. Could it be a clogged O2 sensor? I would assume I'd get a fault for it if it went bad? Any other suggestions? I changed my spark plugs and cables hoping that would be it screen shots showing it when running in neutral and max and min for fuel trim thanks for the help!