[Al Skierkiewicz]

Dude,
Is it possible you are trying to overcome a problem with the joysticks by writing code? I always have to ask...Are your speed controllers calibrated? This simple function will match the extremes on your joysticks to max output on the speed controller. It is very easy to watch the LEDs on the controllers to see where (or if ) they achieve full red or full green as you move the joystick forward and back. If they do not, then calibration is the easy answer. Joysticks also exhibit electrical noise as they move and this may be interpreted by your code as a human commanded direction change.