Confused: P0130 and P0150 code after replacing rear sensors
 

Last night, I replaced the two o2 sensors BEHIND the catalytic converters. The car was running sluggish and I have 160kmi on my 97 E420. I had no O2 related codes before. Now, the car runs much better but I got P0130 and P0150 faults. They seems to correspond to the front sensors that I have not yet replaced. Any thought?:rolleyes:

Rear O2 sensors are there ONLY to monitor catalyst operation & should NOT have any effect on how the engine performs!

Yes, those are front O2 codes. Are you sure you replaced the REAR ones?

Yes, I replaced only the rear ones and then got front sensor codes, very strange... Any guesses?