Hi..I bought a catalyst converter with sensors on it. After two weeks my bank 2 sensor 2 code came on something about voltage..car started running bad sputter..so replaced both downstream with Bosch sensors and heated codes came. Took those off and put old one in bank 1 and bought a catinbow for for bank 2. Car still running bad..fuel is good but gas pedal not right..need some help..thanks

Sorry guys 2002 Q45 176k.

Could you post the actual codes you were getting?

And was the catalytic converter you bought (and installed?) a used part with X miles?
It would help to get more of a timeline of the issues and solutions you have attempted. I'm a little confused as to what exactly needs to be addressed here.

Im sorry but my phone kept refreshing so couldn't really explain..bought catalyst used with sensors on it..After replacing catalyst about 2 weeks code p0158 and p0159 on bank 2 sensor 2 so replaced it with old one from old catalyst. That's when I felt the sputter in gas pedal..same code popped up..p0158'p0159..so bought Bosch sensors put them on both downstream bank 1,2 and got p1041,p1061 heater circuit malfunction on both banks..gas was still sputter..Took them off and put old bank 1 sensor 2 that came with catalyst and replaced bank 2 sensor 2 with catinbow sensor..gas pedal is slower and still sputter a little..nothing like before replacing sensor..I can't understand it..why my gas pedal is not normal..is not burning gas like before but my pedal is not normal..so what can it be..thanks for responding.

bought catalyst used with sensors on it..

Which side catalyst did you replace, right side only?
Why did you replace it - what codes did you have before the replacement?

1. After replacing catalyst about 2 weeks code p0158 and p0159 on bank 2 sensor 2 so replaced it with old one from old catalyst.
That's when I felt the sputter in gas pedal..same code popped up..p0158'p0159..
2. so bought Bosch sensors put them on both downstream bank 1,2 and got p1041,p1061 heater circuit malfunction on both banks..gas was still sputter..
3. Took them off and put old bank 1 sensor 2 that came with catalyst and replaced bank 2 sensor 2 with catinbow sensor..gas pedal is slower and still sputter a little..nothing like before replacing sensor..I can't understand it..why my gas pedal is not normal..is not burning gas like before but my pedal is not normal..so what can it be..thanks for responding.

So are there any codes right now? I can't find any info on the P1041 and P1061 for an 02 Q45 at this very moment.

Do you have the stock air intake?
I would check that system for leaks. It doesn't seem related, but it's interesting that both downstream sensors are correlating with your sputtering.

Also, can you record a video of what exactly your vehicle is doing that you describe as gas pedal sputtering?

The codes were p0141 and p0161 heater circuit malfunction..I had bought both sides in one unit. Y catalyst with sensors. So after removing the Bosch sensors because of the malfunction code. I put the old sensor back on driver side and bought a catinbow for passenger side..so after a day the catinbow sensor is throwing the p0161 code heater circuit malfunction..so that's two sensors that's throwing that code. Either they are cheap or something is wrong..any suggestions on 02 sensors downstream b2 s2