I'm getting a p0161 p0154 p0141 p0134 trouble code on my 97 gmc sierra ?

Question

What could be the cause fuel mileage sucks

Answer 1

Hi there,

These codes indicate an issue with the Heated O2 sensors. However, I would suggest you check the wiring first because it's rare for all O2 sensors to fail at once. Here is some more info for you.

P0161 GMC - HO2S Heater Performance Bank 2 Sensor 2

Read more: https://www.autocodes.com/p0161_gmc.html