Engine hesitation at 3000 RPM

1999 Toyota Tacoma Prerunner 3.4 140000
I had my timing belt replaced along with the water pump about a year ago. Since that, I've been having acceleration problems. If I'm on the freeway and I get on the gas, my truck seems to have trouble finding what gear to be in. The rpm stays at a constant 3000ish rpm even if im on full throttle. If I let up on the the trottle a bit, it then begins to accelerate, but not by much. I have no where near the power and accelartion I had before the timing belt change. Last weekend I had the injectors cleaned, replaced differential and transmission fluids, fuel filter changed, new sparkplugs and wires. Ive notice a little more engine response but I am still having the upper 2500 rpm range power loss. Any ideas?

Thanks