Does anybody have experience replacing the..

[Niceguyeddie]

Just curious what codes it was throwing when you had the whistling sound?
Mine had the whistling sound until I took out the Check valve (96.201.255.07 and 96.201.255.06) and fashioned my own check valve (the check valve wasn't doing its job and was letting air in both ways). It stopped the whistling but I'm pretty sure something else is broken which caused the check valve to break.

Mine is throwing codes
P1124
P1126
P0455

My homemade check valve didn't make much difference (these are the same codes it was throwing before). Only now, it doesn't whistle anymore. I've been running it like this for 6 months with few side effects. It's an old car with high mileage so my expectations are reasonable. I just want to see if I can fix the P0455 code before I replace the oxygen sensors.

And, as this is an old thread, what did you do to fix yours? I have been researching this for over a year and I have some time off this week to troubleshoot. I want to find these parts at a dismantler locally, and replace them one at a time rather than spending what I consider to be too much money on new sensors (each one is over $100 new). It's a gamble either way, but finding the parts at on a junked car with lower miles seems to be a much cheaper route than buying new. I've had experiences buying new oxygen sensors that turned out to be bad from Bosche, but that was years ago and another sob story. I will buy brand new oxygen sensors for this car, but not until I get this P0455 code sorted out. Sorry to Ramble.