Exhaust Having Trouble With O2 Sensors

Front and back connectors should be different and thats the reason for multiple part numbers. Did you clear the codes after screwing with them?

Rarely will you get a DTC code that "says" that an O2 sensor is bad. Most ppl look at the DTC code and see the word "O2" and "assume" that the O2 sensor is bad. It's only after replacement that the real trouble shooting begins.

It would help us to help you if the full DTC codes were posted.

Note also that the back number #2 sensor is used to monitor the Cats. A problem with either #2 sensor will not cause a drivability issue.

For the Mustang, the #1 and #2 O2 sensor are the same. From the factory, the color of the O2 pig tail is different. Hence the the different part #'s.

The front O2 sensors control Air/fuel ratios. A problem with the fronts will affect how the motor runs.

The rear O2 sensors MONITOR the cats. A problem with the rears will NOT affect how the motor runs.

The replacement O2 sensors are the same for the fronts and back as well as left and right. The after market is not concerned with the color of the factory pigtail.

Sooooo have you concluded that the O2 sensor itself isn't the problem since the DTC code is unchanged?

It ties the hands of the ppl trying to help you when you don't post the full DTC codes. However, if this is a circuit fault DTC code, the usual causes are:

• Water in the connector
• blown fuse
• Burned, pinched, chaffed wiring harness.
• bad PCM