" I thought it was obvious that the front O2 sensors are the important ones. You wasted your money for the rear sensors. Those don't have anything to do with misfires. I run without any rear O2 sensors (downpipes are plugged instead) and the car runs perfectly. "

" I would say replace the O2 sensor on the bank with problems. Or even better, replace both of them, because the labor costs are high. Also log the low fuel pressure, etc. I remember someone having some misfire problems with the fuel pressure sensor and solved them by replacing it. "