Oxygen sensor failures, gas station related? White ash on sensor?

[Cujet]

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.

 

[spasm3]

Are you thinking that leaded av gas got in the tanks at that station?

I usually replace my upstreams around the 90k mark.

 

[Kira]

What code(s) accompanied the CEL?

 

[brianl703]

Someone put E85 in the wrong tank? Do they even have E85 there?

 

[Cujet]

Are you thinking that leaded av gas got in the tanks at that station?

I usually replace my upstreams around the 90k mark.

No, this is at Palm Beach airport. I don't even think they have any 100LL Avgas there anymore. It's just jets. I'm thinking the O2 sensors were weak and poor fuel quality from the very busy (and cheap) airport gas station causes enough contamination to disable them.

 

[PimTac]

Sounds like something a fuel additive would do. Assuming that you haven’t used any additives, would the station dump something in their tank for whatever reason?

I probably wouldn’t use that station anymore.

 

[skyactiv]

I'd contact Sunoco about it. Some fuel brands have a gasoline quality guarantee.

Example:

https://www.udfinc.com/products/udf-fuel/

 

[mk378]

I'd contact Sunoco about it.

It was Mobil gas from a particular station that was suspected. Using Sunoco made it better.

 

[eljefino]

I'm just shocked the airport gas is cheap. Usually it's a ripoff to get tourists with rental car returns.

Grey deposits cover every o2 sensor I've pulled. I only had one turn "lazy" (P0133) and lost one heater element, over my life of maintaining high mileage hoopties.

 

[skyactiv]

I didn't read the post

 

[AZjeff]

And yet gave a recommendation.

Avoid the Mobil gas X2. Hard to prove their gas caused the O2 failures but you've observed poor performance.

 

[wemay]

It's very odd considering you mention it's a busy station. That would imply a fresh supply of gas. I was always taught to avoid non-frequented ones. Might it be the additives mixed in?

 

[bullwinkle]

I’m puzzled by the gray ash deposits-isn’t that usually an indication of oil consumption? Maybe some diesel is getting in with the Mobil gas?

 

[Cujet]

I’m puzzled by the gray ash deposits-isn’t that usually an indication of oil consumption? Maybe some diesel is getting in with the Mobil gas?

Not sure. One thing is also clear, the 3.5EB bucks a little on full throttle acceleration with the bad gas. And the 5.4L V8 pings a little with it.

I'm guessing the Mobil station simply uses the cheapest swill available. Prob with fewer additives, but not sure.

 

[chemman]

I would report that station to ExxonMobil in case they are buying gas elsewhere. Several years ago there was an Exxon station in our county that was right off the interstate and was selling gas for a lower price than anyone else in the area. They also had a big sign saying "Thank You Exxon". Well, it turned out they were not selling Exxon gas exclusively.

 

[Wheel]

I remember a few years back, Pilot had issues with high sulphur content in its gasoline. It caused problems with fuel level senders and O2 sensors. If I remember correctly, they ended up repairing those issues for customers with problems.
I don't know what the failed O2 sensors looked like, but it might be worth mentioning to the station.

 

[350Rocket]

Is Mobil not top tier?

 

[Tkonrr]

Gas station employees have been intentionally putting 87 octane in high octane tanks and water in all tanks forever. With record high gas prices, theres probably extra water and less additives added.

 

[350Rocket]

Gas station employees have been intentionally putting 87 octane in high octane tanks and water in all tanks forever. With record high gas prices, theres probably extra water and less additives added.

I've never heard of this. Any proof?

 

[HankHill]

I've heard of water leaking into gas tanks, just never heard of someone intentionally placing it in there..

My aunt was a district manager at Cumberland Farms. She did audits for the most part, all day long. She said there is an admissible amount of water they can have in the tanks without causing any issues, and that every tank had an amount of water in it... I did not have the chance to ask her what would be done if the amount of water was too high.. My bet? Nothing..