[piper6909]

Originally Posted by Vza

99 Boxster Base So after much work and money. New Batt, AOS,MAF,Plugs,Fuel Filter,Air Filter,Gas Cap,Oil Cap o-ring,Cleaned TB, Timing,New VarioCam Solenoid, Repaired DME, I'm getting a CEL with P1123 P1125 codes every 600 miles or so****for rich fuel on both banks. Checked as best I could for vacuum leaks, Fuel regulator I think is within spec for vacuum Maybe on the low side. Any thought as to what I do next. Car is running good says I'm getting 26 MPG on the H'way which is hard to believe. Out of ideas!!! V

You've already thrown the kitchen sink at it, so I can't imagine what else to try except the air/fuel ratio sensor.