Tundra Alc. density and fuel trims

My 2013 Tundra 5.7 FLex 54000 miles started having dreaded Alc. Density issues. I used OBD II to monitor Temps, but I have not used Alc. Density in awhile until the other day when I noticed my fuel trims went up. Before this I visited a dealer for an oil change so maybe they did something on purpose . My fuel trims before this were around -6 on both banks. I always used 91 premium or Ethanol free. I had TSB done in 2013 and there were no issues until now. My Alc. Density shows 36% and my Long term fuel trims are in -14. Short trims are fine. I took it to a dealer and they would not do any re flash or reset without charging $500. They said my ECM has the most recent update and TSB has been done. (my powertrain warranty expired 2 months ago). I have no DTC codes, truck seems to runs ok and MPG is the same. They want to do bunch of testing for $500 when I just asked them to do Alc. Density reset. They wont do it. Called Toyota and they said they stick with dealer recommendation. What could be wrong?

 

Hey, just wondering if you were ever able to get this resolved.

My 2014 has had the same issue for the last 5 years. It's been to the dealer 5 times. They usually just reset the fuel density calc and the problem goes away for 2k miles, then it comes back every time.

There is a new 2019 ECU update to supposedly fix the problem. I had it done 2 months ago and sure enough the problem is back after 2000 miles.

Toyota corporate has been covering the cost since I reported it before the powertrain warranty expired. The truck has 90k miles on it now.

When the ECU calculates the density right, I get close to 17mpg on the highway. As the density creeps up I get as low 8.3mpg. This is a very expensive defect.

When the fuel density gets really high, the truck experiences extended crank and excess smoke comes out of the tailpipe.

Did you have any luck resolving this?