Sluggish shifting.

Hello everyone!

I have a 2007 tundra base v6. Just a work truck. 274xxx.
Super sluggish acceleration intermittently. 90% of the time its sluggish, 10% runs like a champ with zero issues. Put it into drive, runs good to about 15 20 mph, after that doesn't want to put power to the wheels. Rpms rev, but very, very little power. Eventually when I get up to speed, she shifts fine, then, little power again.
I thought it was a tranny issue. First guy I went to said no, not the tranny. Pressure check on the cat was good, he said the throttle body solenoid was bad, so he replaced it. Was good for the day, now back to sluggish. Brought it to a Firestone, they said transmission and the first guy didnt know what he was talking about. I really dont think its the tranny, because when it's runs good, shes good. Not a misshift, no banging into gears just a strong tuck with no problems.
I am throwing a secondary air injection valve code, that I have been ignoring as I'm in FL, and fl doesnt care about emissions, and everything I read on forums lead me to that 100% not being the problem, mechanic and Firestone agreed. No other codes are coming up. Anyone ever run into this??

 

secondary air injection code will 100% put you into limp mode

 

It's been running fine with this code on for months, why would this be happening now? What could have triggered it? And why would it be intermittent? What's the cheapest way to fix this?

 

The limp mode is to prevent fire. If the valve sticks open after the pump shuts off then hot exhaust can go up the pipe all the way back to flammable stuff. If it's just the pump code without the valve I don't remember if that triggers limp mode or not.

Either get the system fixed or there's the hewitt-tech bypass kits for less $.