94 Z24 auto trans issue HELP

Just want to make sure I'm troubleshooting this right. Car will stay in drive when coming to a stop. torque converter doesnt seem to be unlocking. When running down the road normal passing acceleration unlocks the converter or at full throttle. However when I step on the brake it does not unlock. I am assuming the tcc solenoid is bad. Also if I am at about 10mph and the engine is lugging a quick snap of the throttle to the floor unlocks the torque converter and shifts it into 1st gear. Only does this after about 20 minutes of run time, when cold it works great.

The TCC should not apply when the engine's cold (makes it heat up to operating temp faster unapplied), so that's probably why it works fine then. If it unlocks for high throttle, I would start by making sure the PCM is seeing the brake switch 'on' when you hit the brake.

guess I should have clarified. the engine warms up, torque converter locks up and works normally for roughly 20 minutes of drive time. I guess I was under the assumption that the computer would read closed throttle and release the torque converter, or vise versa when the brake was applied I thought that released the torque converter also. Maybe I'm wrong but.... these are also the only electrical reasons to unlock the torque converter???? What makes the torque converter unlock under acceleration like when passing a car???? It works normal under light/moderate acceleration.

The TCC should release under high engine load (which I believe is MAP sensor, not TPS but I could be wrong) and when the brake is applied. I don't believe it should unlock based only on 0% TPS.

What's the fluid like? Dirty fluid can cause TCC solenoid problems.

Fluid is flushed and filter is changed after engine swap. I resurrected this car from the shelter belt. big brother overheated and siezed the engine solid, trans was working great previously.

It's probably a bad solenoid then. Make sure it isn't being commanded on or there is a short that is making it apply.