Ok, this is strange. My 545 has had plugged sec. air ports on bank 2 now for a couple years. I also had leaking valve stems seals that I just replaced several months ago. Last weak, my CEC light turned off and has not returned since. What changed? My guess is that solving the excess oil in the cylinders allowed the carbon to burn off that was plugging the air ports. A little hard to believe, but what else could it be? BTW, I was unable to clear the ports with AGA's cleaning tool (at time of valve stem seal changing).

Whatever the root cause, I hope it lasts