Hey guys,

So I have a 97 Lesabre that is simply a daily driver. It wasn't getting any codes, but the fuel trims were goofy and the fuel economy was down. Replaced all the vacuum lines and what not, 90% sure there is no vac leaks, so I replaced the 02 sensor.

Fuel economy is up, LTFTs look good now, car runs great, but I am getting a P0133 code that I did not have before. Naturally, I'd think I just got a bad O2 sensor, but this is a Denso unit and I've never had any problems with any of the half dozen or so I've used in the past. Should I go ahead and return the sensor for a replacement, or should I try something else first?