Toyota Repair: transmission shifting, throttle position sensor, continuity tests

Question
Ted, I have a 91 toyota camry,3sfe engine and the A140E transmission. The problem is that it doesn!t shift properly. From go it takes a long time to shift and once it shifts you have to excellerate to get it to shift again. Once it gets to high/overdrive it doesn't stay it shifts in and out. If you excellerate rapidly it seems to shift normal, but still will not stay in OD. I have had this vehicle in a local trans.repair shop where they finally gave up on repairing it. They replaced the shift solenoids in the trans., replaced valve body, throttle position sensor, and finally totally rebuilt the transmission. After 3 weeks in the shop the trans. is basically the same as it was when I took it in  for repair. I changed the ETC ECU from a salvage yard,no help! Do you please have a word for me that will convince me not cut my losses, the engine in this car runs great.THANKS, BILL

Answer
The only thing that wasn't replaced was the wiring, there could be an open circuit or short circuit in the wiring associated with the transmission or the computer has a bad ground connection, it will take someone that can do this kind of diagnostic work that involves looking at the wiring diagram and doing some resistance and continuity tests between the ecu and the transmission, this is going to be time consuming and expensive but I just have no other idea what could cause the problems.