Once in a while, I get a PO171 code. Car runs fine, so I put it out. Replaced Map Air, and two Bosch upstream 02 sensors. But it still comes on once in a while. Dealer says new sensors aren't OEM so they don't see the voltages changing the way they should. I can't find any new OEM 02 sensors, and I wonder if that is my actual problem. I could use some help. Thanks

 

Bosch sensors don't seem to work well with Chrysler products. One would think that could be your problem except that the Crossfire was actually a Mercedes product. Might want to get some sensors from a Mercedes dealership and try those. The other consideration is that the way O2 sensors work is that the computer compares the readings from the upstream sensor to the reading from the downstream sensor to determine how well the catalytic converter is working. As the sensors age with use, the ratio should remain the same. If you change only the upstream sensors, the computer is trying to compare the reading from a new upstream sensor to the reading from an old downstream sensor and it's getting confused. Changing all sensors, up- and downstream at the same time might solve the problem.

 

I had the same issue with my car after closer inspection I found a crack in the top of the catalytic converter on the driver side, right in the seam , removed the driver side, exhaust pipe, and re-welded the seam with stainless steel rod. No more problem. All is well.