Love the ride and feel of the truck,coming from a 2008 tundra 5.7 this truck feels slow under wot,almost surges at times like the computer is closing the throttle body .I can smoke the one wheel from a dig no problem but at about 40 mph or so it seems to surge..not knocking the truck, love it compared to the tundra but were is the 390 hp they claim..truck is stock 2012 express 3.55 gears...
Are you looking at your rpm when this occurs to tell what rpm you are at during this "surge"? I know you said "40 mph", but are you hitting a rev limiter or something that's giving you this feeling? Without a couple of other hard numbers, it may be hard to assess your performance just by feel. I have the same year and gearing as you, and mine revs up so quick and hard that it's almost scary.
if this is a brand new truck, and others can correct me if i am wrong, but there may be a computer code that detunes your truck some until you get some miles on your truck. mine seemed to wake up after 500 miles or so, or it may be the computer learning how you drive your truck.
It's the combination of Variable Valve Timing, Variable Intake Runners, and Torque Management. The torque management will kill you from a stop and the surge you feel at about 3000-3500 rpm is the variable intake runners opening up. I hope this helps. If our 2011-12 trucks could be tuned, torque management could be removed. The removal of torque management makes a TON of difference.