I've never driven one with an auto, but I've heard nothing but terrible things about them, that added with the tire size might contribute to the sluggishness.
Maybe check injectors/clean/replace??? Do a tune up with all OEM parts from toyota. No fram, autolite, K&N, junk stuff.
Edit: Check the positioning of your Throttle Position sensor. Get a Toyota shop manual, feeler gauges, and ohm meter and check resistance and clearance of the throttle body. Pretty simple to do.
