Engine Light Coming on....Very strange

[TNJYOUNG]

Good morning fellow Tahoe/Yukon owners. I have a 2013 Tahoe with just over 120K miles. I bought it with ~85k miles on it and I have owned it since. At about 100k miles I filled the tank with 93 octane, 100% (no ethanol) gasoline. I have always had the practice of running a tank of "super unleaded" occasionally through any vehicle that I have owned.

Within about 100 miles of filling up my "check engine" light came on so I stopped at a local Auto Parts store to have them hook up their diagnostic computer to read my codes. The code read "oxygen sensor" at the catalytic converter Bank #1 or Bank #2 or something like that. Thinking it needed this part, I contacted the dealer than they gave me a price on replacement. The price was pretty high and I remember thinking "yeah, it probably needs this, but I just filled up with a different gasoline, too, so this is odd"

So I drove out that tank of gas, engine light on the whole time, and stopped to fill up again. This time I filled up again with the cheapest 87 octane (with up to 10% ethanol) gas that I could find. I drove off and within 30 miles the light went off. The light stayed off for over 1.5 years.

This past weekend I took a road trip and was about 100 miles away from home and needed gas. I pulled in to get gas and I don't know why, but I filled up with 93 octane (100% no ethanol) gas again. Same story as before. By the time I got home, the check engine light was on and the first start in the mornings felt a little rough.

Also, like before, I ran out that tank of gas and filled up with the cheapest 87 (with ethanol) that I could find. Also like before the engine light went off and the truck is running smooth again.

Anyone else experience this strange phenomena?

 

[OR VietVet]

This is like when you go to the doctor and tell the doctor that when you raise your left arm up to your shoulder it hurts. Then the doctor looks you in the eyes and says, "Well, don't raise your arm up there then". Someone will likely know why but I don't but the story is interesting. What does your owner's manual say about the type of fuel that is recommended for the engine?

 

[Fless]

I think it would be incredibly helpful to know which specific code is setting the CEL.

 

[OR VietVet]

Yep, they assign code NUMBERS for a reason, huh.

 

[TNJYOUNG]

This is like when you go to the doctor and tell the doctor that when you raise your left arm up to your shoulder it hurts. Then the doctor looks you in the eyes and says, "Well, don't raise your arm up there then". Someone will likely know why but I don't but the story is interesting. What does your owner's manual say about the type of fuel that is recommended for the engine?

LOL! You are right! Owner's manual simply states 87 octane or higher.

 

[TNJYOUNG]

I think it would be incredibly helpful to know which specific code is setting the CEL.

I had the codes pulled the first time this happened in late 2018 and I no longer know what codes they were. I did not have the codes pulled this time.

 

[PG01]

0420 and or 0430 probably. Your o2sendors not liking the super gas. Unless the engine is tuned I would stick with 87

and yes, every few years i get same codes in my 13 hoe but i use 91-93 all the time...

edit: sorry, it is probably 015b or 015d delayed response from either 02 sensor

 

[TNJYOUNG]

0420 and or 0430 probably. Your o2sendors not liking the super gas. Unless the engine is tuned I would stick with 87

and yes, every few years i get same codes in my 13 hoe but i use 91-93 all the time...

edit: sorry, it is probably 015b or 015d delayed response from either 02 sensor

Thank you. Yeah, my truck doesn't have the green "Flexfuel" logo on the back, but I often wondered if these things were made to work well (better) with a little corn in the gas? Thank you for letting me know that I am not the only one getting codes like this occasionally.

 

[PG01]

 

[PG01]

Thank you. Yeah, my truck doesn't have the green "Flexfuel" logo on the back, but I often wondered if these things were made to work well (better) with a little corn in the gas? Thank you for letting me know that I am not the only one getting codes like this occasionally.

But if its a 13 and the gas cap is yellow its flex fuel