Lately, all of my vehicles have experienced O2 sensor failures (check engine light). Now, I know that the vehicles all have high miles, and O2 sensors often have a finite life and had probably reached the end of their practical lives. Also, I've been driving quite a bit and purchasing fuel where I need to.
However, there seems to be one specific trigger for the check engine light on my 2011 F150 3.5EB V6, a Mobil gas station at the airport. I can reset the codes and it will come right back. But if I purchase gas at Sunoco in another town, the MPG goes back up to near normal, and I do not get any codes. Go back to the airport Mobil station and the light is back on before I even get to the highway.
Also interesting is that the 02 sensors on my 2009 F150 5.4L V8 were covered in white powdery ash. The engine uses no oil what so ever, uses no coolant, and has had no maintenance. Same results too. Purchasing fuel at Sunoco results in no check engine light.
As you might imagine, replacing the sensors resulted in slightly better MPG.
However, there seems to be one specific trigger for the check engine light on my 2011 F150 3.5EB V6, a Mobil gas station at the airport. I can reset the codes and it will come right back. But if I purchase gas at Sunoco in another town, the MPG goes back up to near normal, and I do not get any codes. Go back to the airport Mobil station and the light is back on before I even get to the highway.
Also interesting is that the 02 sensors on my 2009 F150 5.4L V8 were covered in white powdery ash. The engine uses no oil what so ever, uses no coolant, and has had no maintenance. Same results too. Purchasing fuel at Sunoco results in no check engine light.
As you might imagine, replacing the sensors resulted in slightly better MPG.