Hooked my scan tool up to my 2001 gt today to live data to check the o2 sensors. Bank 1 sensor 1 volts went from 0.120 to 0.745 which I think is normal. bank 1 sensor 2 read 0.000 at all rpm's with short term fuel trim read 99.2 %. Bank 2 sensor 1 had a volt range of 0.120 to 0.700 with a stft reading of 8.6 to 19%. Bank 2 sensor 2 volt range was 0.04 to 0.2 with stft of 99.2% .Am I correct thinking that both side down stream sensors are bad? My car does not have a stock exhaust. There are no catalytic converters. It has a straight pipe coming off the exhaust manifolds going into a H pipe. All 4 o2 sensors are in the short part of the H pipe where the pipes meet. From there it goes into flow master mufflers. This was all done by the previous owner. Wondering if this set up could be the problem with the downstream sensors. My car throws code p0174 which is to lean bank 2 and code p0153, o2 sensor bank 2 sensor 1 slow response.