Alright guys I’ve been having problems with p0135 and I know the code reads bank 1 sensor 1 and it’s the sensor closest to the engine on the passenger side. I have already replaced the sensor with brand new motor craft ones and the code still appears even after I reset the code with my scan tool or if I unplug the battery for 30 min. I did check for shorts but everything electrical seems fine. However I do notice that when I’m on idle the car starts shaking for a bit and then it stops and idles back to normal. I checked this with my scan tool and I saw that bank 1 runs lean when this happens. I’ve been told it might be a vacuum leak and I did a smoke test on the engine and I didn’t see any smoke. I also did the test on the exhaust tip but the smoke just comes out from the other exhaust tip (dual exhaust) Im guessing I did the smoke test wrong or maybe the problem is somewhere else i don’t know. If anyone has an idea of what it might be or a solution it would be greatly appreciated. One last thing. Sometimes the check engine light goes off on it own without resetting but it comes back later on.

 

the Code is specific to the heating circuit and not necessarily the O2 sensor. That means that the O2 sensor may be fine but the circuit/wire harness going to it may have a short or is broken. Have you traced the wire all the way back to the main harness and back to he PCM? This thread will show you where to find the other (upstream) connection(s) point of the O2 sensors. Should be the same for GT.

Post 5
https://www.allfordmustangs.com/foru...g-diagram.html


Post 5 is the pin-out of the O2 sensor connector so you can test the circuits.
https://www.moddedmustangs.com/forum...nsor-fuse.html

 

Yeah I found this troubleshoot test for the car and I get a reading of volts and resistance from the sensor to the pcm. I had to buy extensions to make testing easier for me.