High % Alcohol Content Reading

[paoloaccount]

how I know that my truck's reading high alcohol content is by how it starts in the morning. It will sound like something misfires but then it will start up. I started this post because I need recommendations where I can get the right scan tool or exactly what scan tool to get that can reset the Alcohol Content Reading? please help!

[demech23]

You'll need to go to a dealer and request them to perform an alcohol percentage relearn procedure with their GM tech2

[tbarn]

Man, if diagnosing were that easy.

[demech23]

More so experience. My truck used to do the exact same thing; on cold starts it would run like a misfire while RPMs would be all over the place. Would get as low as if it would stall out, but after some time it would run completely fine and there would be no check engine light or codes present. I've always used top tier fuels and drive 10 miles after fill-ups. Throughout the years this probably happened about three times. Found calculated alcohol percentage to be from 47 to 52%. Looking back, It happened shortly after adding complete fuel system cleaner prior to my oil changes during the winter months. I was able to turn off my trucks alcohol percentage relearn procedure, and have luckily not had any issues since.

[paoloaccount]

More so experience. My truck used to do the exact same thing; on cold starts it would run like a misfire while RPMs would be all over the place. Would get as low as if it would stall out, but after some time it would run completely fine and there would be no check engine light or codes present. I've always used top tier fuels and drive 10 miles after fill-ups. Throughout the years this probably happened about three times. Found calculated alcohol percentage to be from 47 to 52%. Looking back, It happened shortly after adding complete fuel system cleaner prior to my oil changes during the winter months. I was able to turn off my trucks alcohol percentage relearn procedure, and have luckily not had any issues since.

is relearning alcohol percentage procedure different from resetting the alcohol content percent back to normal? I just got it reset back to normal and have been doing the "good" habit of refilling the tank, top tier(Shell) gas station and driving 7 or so miles. After my second fill up, I can sense that it was reverting back to how its starting, meaning alcohol content is beginning to read higher again.