I recently purchased a 94 runner 3.0 V6 which accelerates on takeoff very poorly. I have heard of this engine to be sluggish, but to the point of taking 60 seconds to reach 30MPH? I think I may have an air/fuel mixture issue. If this is the case, how do I attempt diagnosing and repairing this issue considering the fact that it is not giving me any trouble codes?

Repairs and test performed so far with no improved results are as follows:

O2 sensor & TPS sensor replaced, cat converter removed and inspected with no signs of any restrictions; rotor, cap and plugs replaced, fuel filter replaced, throttle body inspected and cleaned, MAF sensor tested to be good.

What am I lacking? I figured all that would be enough to fix the problem. Any ideas of other repairs I can try before resorting to a mechanic or the dealership for help?