When I'm in 3rd (D), and OD is locked out, I can slowly accelerate and the torque converter will be locked up. I can keep on acclerating slowly, and then when my throttle linkage hits a certain spot, the torque converter unlocks. Yes, I know it's the combination of the TPS voltage, at the higher end of the throttle, and the PCM knowing I'm in 3rd with OD locked out, but what is the point behind it? Is the only thing I can do, other than backing off the TPS, is to install a lockup switch?