I don't believe for one second all 4 are bad. Perhaps 1. As has been suggested by others, get a code reader to verify what codes are stored. IF an O2 sensor code is present, switch the drivers side (up stream or down stream depending on the code) with the passenger side. If the code changes from drivers side to passenger or vice versa, you have found the bad sensor. I did this, a new ebay Bosch sensor, around $80.00, and life returned to normal.

Les