torque convertor probs.

I'm new here and any help I can get would be greatly appreciated. I have a '92 with 4.0 and aw4 transmission. Transmission has been serviced regularly. Whats happening is when the torque convertor locks up the only way for it to unlock is to depress the brake pedal. If i need to accelerate say up a long grade i need to hold brake pedal while pressing the accelerator. Also tps has been changed but this did not solve the issue. Any help would be great.

i believe the tcu controls the lock up, it might be bad, if u search u might be able to find how to diagnose it with a meter, not real sure, check fuses and relays is all i can suggest goood luck

I unplugged the tcu and let it sit for an hour and plugged it back in. no change. anyone have any ideas how to test if its bad.