tranny or TC problem?

Here's what's happening:

From idle to about 2500 something is slipping. I can go WOT or 10% throttle and it seems like something is lagging. The RPMs accellerate very slowly until about 3000 RPM then something catches and it goes like normal. I can't figure out if this is a tranny problem or a torque converter problem. It almost feels like the TC is stalling up, but horribly exagerated. Also I know my tranny is in sorry shape, but I would think if it's a tranny problem it wouldn't only slip below 3000. above that rpm it shifts and runs fine.

Any insights would be appreciated.

its sounds like what many people are suffering with, i know on mine it feels like at low rpm range it boggs untill 2500 and then it catches and throws you in the seat. im thinking it is loading up with fuel, so im going to be changing vacuum lines, fuel injectors, o2 sensors, fuel pressure regulator, spark plugs. and ill throw in a new opti and wires because mine is at 146xxx miles.