We have experienced this problem on many Toyota's that we have worked on. It is most notable when actuating the tilt circuit. I believe that the engine is undersized and no amount of tuning it up or cleaning out the carbon will rectify the situation. TCM had the same problem, so what they did was add an "idle up" device to the carburetor which bumps up the RPM's when the engine is taxed. Typical Japanese technology, instead of using a powerful enough engine that might raise the price of the truck they install a $12.00 item to hide the fact that the engine is too small.
Well anyway, we have had many Toyota users complain about the stalling and we have been retrofitting the "idle up" device onto the carburetor and it stops the truck from stalling.