I have an '06 Dbl-Cab Tundra with approx. 93k miles. Recently it began 'stumbling' on acceleration at highway speeds. I tried to be more attentive, and notice that it only happens at a speed of 50-60mph, approx 2000-2200rpm, when I ease down on the accelerator to slightly increase speed. It makes no difference what terrain (level or hill). I have no active codes, and the light has not come on. It feels like a misfire, but I can't rule-out the transmission shifting somehow and causing it, because I don't 'hear' anything, just feel the 'jerk'. Afterwards, I can accelerate and decelerate just fine with no more hesitation or jerking.
Oh yea, to make it more perplexing, it doesn't always happen. It may happen several times one day, then not again for a week.
I don't have any specialty Toyota tools, but I do have digital multi-meters, digital-storage o-scope, code-reader (Autozone model), and schematics from alldata if someone could point me in the right direction toward something to check.