[jhv48]

For those of you with a light surging (bucking) at cruising speed, that usually is the result of a slight lean condition. Try opening up the idle air screws a quarter turn and see if that helps. If it does, then screw them back in until the surge returns and then back them out slowly till it disappears. If it doesn't, take your primary jets up a size or two and re-test. Light cruising is generally on the main jet system.