Instead of going through the throuble of measuring TPS output voltage, you can try rotating your main throttle sensor by almost 1mm by relating to the green index mark. You can then rotate subthrottle sensor also counterclockwise to reduce cold-engine fast-idle rpm if desired...
Look at the main (grey) throttle sensor's green alignment mark on its front from near your front left flasher, and note how it ligns up. Loosen sensor screw with T25 Torx tool. Rotate sensor counterclockwise by about half a millimeter as seen on pic. Adjust, then tighten Torx screw. Main throttle sensor's new position:
Main throttle sensor Torx screw:
Fast idle may then be higher. You can rotate subthrottle sensor (black, just above main throttle sensor) also counterclockwise with T25 Torx screw to reduce cold fast-idle rpm. I rotated mine to its maximum counterclockwise position, to which it was already near. Subthrottle sensor's new position:
This also smooths out throttle response at low speeds. The left TB's left IAP sensor hose fitting bore is larger than in the two TB vacuum access fittings. A 6" long, 1/8" ID hose on both TB vacuum access fittings which originally had the rubber caps on, works perfectly.
According to service manual:
"Throttle Grip Free Play: 2-3 mm
If the throttle grip doesn’t return properly, check the throttle cable routing, grip free play, and cable damage. Then lubricate the throttle cable.
To adjust, loosen the locknut at the upper end of the accelerator cable. (under throttle grip) Turn the adjuster in completely so as to give the throttle grip plenty of play. Loosen the locknut at the middle of the decelerator cable. (see pic) Turn the adjuster until there is no play when the throttle grip is completely closed. Tighten the locknut. Turn the accelerator cable adjuster until the proper amount of throttle grip free play is obtained. Tighten the locknut."
You can easily pull the mid-cable adjuster that runs over the engine, adjust it then check with cable back up in its natural position. Shown here with locknut loosened and backed up to the right: