I wasn't refering to the throttle cable for the engine. If you read my post you would see I was refering to the throttle cable that attaches to your transmission that sets the throttle pressure inside your tranny. Basically heres the history of trannies some trannies used to use vacuum to tell the tranny what kind of load you were giving the engine some other manufactureres went to a cable that was directly linking to the throttle that when you pushed on the throtle it would also move a valve in the valve body which would boost pressure adaquetly to the amount of throttle pressure in order to shift your tranny later or sooner. Then in newer vehicles it has an e.p.c. (electronic pressure control) Which basically looks at your t.p.s. voltage to determine the pressure to set in your tranny, then the tranny looks at different sensors to determine the shift points. Think of your throttle valve as a piston in your engine, the more it moves back and forth the more wear occurs on it, so the THROTTLE PRESSURE CABLE has an adjustment on it to compensate for slight wear do to wear that may occur in the bore of the throttle valve.
Also firm does not = rough. The best posible shift you can have is a quick firm shift.