Northstar Engines and System Technical Discussion Discussion, P0153 - HO2S Slow Response Bank 2 Sensor 1 in Cadillac Engine Technical Discussion; Have a 1998 Deville, with 78K miles, at 60K, I had encountered the PO153 code (HO2S Slow Response Bank 2 ...
By your statement, the FPR may have been your problem all along. O2 sensors react to rich and lean mixtures, so a rich condition caused by a raw fuel leak would surely mess up the air/fuel ratios and therefore the "expected" values set into the O2 sensor specs.
The Bosch sensors are made for multiple applications, while in theory they should work the same no matter what they are in, who knows?
I have seen a lot of Bosch replacements fail, N*'s do not like Bosch plugs for sure.
That code should be an actual sensor malfunction, a specific set of conditions need to be met for that code to set.
The only really important thing to remember is that Bank 2 is the front bank on a N*.
Some people think it is the rear one.
I don't see a lot of Delco part failures on O2 sensors, seems like buying one factory one would be cheaper than buying 3 Bosch parts.