Hesitation??

so, maybe you all can assist me.. my 93 Legend has a hesitation when in high gear and accelerating from a constant speed. It seems only to do it after its at operating temp. I replaced thus far: O2 sensors, plugs, wires, injectors, fuel filter, main relay.

I cannot confirm if its fuel/air or transmission, though my mechanic couldnt ID anything engine related, and did say he heard a knock coming from the trans. Trans does not leak, and fluid is good and at the correct level.

it has thrown code 44 a couple times, but it disappears after shutting it off, and only has come on 2 times..both times prior to the above hardware replacements.

any ideas?