Methods and apparatus are provided for adjusting a throttle of a vehicle engine. The apparatus comprises an input sensor configured to provide an input signal having a value that approximately corresponds to an operating level of the vehicle engine requested by an operator and a memory configured to store a maximum input value for the input sensor. The maximum input value provides the value of the input signal that approximately corresponds to a maximum operating level of the vehicle engine. The apparatus is further configured to receive the input signal and access the memory to retrieve the maximum input value and further configured to update the maximum input value with the value of the input signal if the value of the input signal is greater than the maximum input value.