CHICAGO – Motorists are expected to benefit from stable pump prices this Mother’s Day weekend. According to the American Automobile Association, the lackluster movement of prices can be attributed to higher demand for gasoline but a lower cost for oil, canceling each other out. Illinois’ average for a gallon of regular gasoline is below $4 at $3.92 cents per gallon. In North Central Illinois prices have remained unchanged this week with LaSalle County priced at $3.72, and Putnam and Bureau county prices steady at $3.80 cents per gallon.