It’s me. I’m the problem

Hey
So I’m a shade tree mechanic and have a couple newer vehicles and figured it’s time to get a scan tool. I got a Launch x431+ off Amazon and have been fumbling my way around.
My 2013 silverado 2500 is having issues with the alcohol content readings. It will creep up to 30% or so. I’ve been resetting it a couple times and it’s good for a couple weeks.
Anyways, just here to try and learn.

Welcome to the Forum.

My first question about your fuel composition is:

When you put gas in it, do you fill it up? Or, do you put in $10-$20, at a time. Fuel composition is calculated by a number of factors. A couple of which are Miles driven, and Fuel gauge movement. Repeatedly putting small amounts of fuel in the tank can skew the calculation.

Hey
Thanks for the reply. I live in the sticks and always fill it. I’m not sure $10-$20 would even move the gas gauge at these prices lol. I usually fill at Costco and the dozen people behind me usually wonder if I just forgot to check if the tank is already full. So many morons wait 15 mins to save 8 cents a liter yet get $9 in their civics, ugh.
Mine takes $200 to fill. In fact my credit card qualified my tank fill purchase for financing, how sad is that?
Anyways I’ve had to reset the ECU alcohol content a few times now and it just climbs on its own. I’m going to put new plugs in and do a tuneup to eliminate the simple. I’ve gotten ‘too rich’ codes a couple times until recently it threw a couple ‘too lean’ codes. So I’m sure that will help me narrow it down. I just need to learn how to better use my scanner I think.
Thank again, and I’m always up for suggestions.