Speed Control Springs problems of the 2002 Buick Lesabre

Accelerator pedal requires excessive amount of force to depress the pedal. This results in a noticeable surge when going forward from a stopped position. It almost feels as if there is spring holding the throttle open and there is a break point at which the spring lets loose before the throttle opens. A visual inspection of the throttle and throttle body did not reveal any obstructions or binding cable. The floor mats are not a factor in this problem. Problem is most noticeable after the car has been started and placed in the drive position. This problem has persisted for the past several years and is the same in both winter and summer. I have just learned to live with it and expect a slight jolt when moving forward but I have been unable to find the root cause and I worry whenever someone else drives my car. This surge is noticeable to passengers also.