The 99's have electronic throttle control which replaces the cable that used to pull the throttle open with a sophisticated servo that is electrically opened due to commands from a sensor that is part of the accelerator pedal. With this sytem you gain the ability to regulate throttle for other purposes.

The ABS control unit monitors the wheel speeds and when there is a sudden, excessive speed increase it will attempt to slow wheel through application of brake to that wheel. If this is not effective OR if you are above the speed range that the brake application is active (0-25 MPH), then the throttle alone is used to suppress wheel spin tendencies. The STC lamp blinks when it is functional to let you know why the car isn't going as fast as you are expecting it to based on how hard you are pushing accel pedal.