As agsy, said above, higher octane fuel is the fix. I started using the mid grade Exxon, I think it is 89 octane. Three tanks now and shifting is good now, shortly after changing. About 40 cents a gallon more but I can deal with that. At least you do not have to worry about getting run over from the sluggish issue. Thanks agsy for the help.
2016 White Colorado Ext. Cab.LT 3.6 V6 6 Spd. Automatic 2WD 3.42 Gears:
Factory Fender Flares (Dealer installed)
BAKflip G2 Tonneau Cover
Curt 51140 Brake Controller
GM Black Bow Tie Set
Factory Towing Package w/7,700 lb. hitch
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