Ive got 01 cavalier 2.2L 4 spd auto, Been notincing lately, From long 140 km driving distance around trip to the city, bogging in the throttle,Their is no back firing my car has 196,800 kms on it, No check engine light, plugs / wires / fuel filter / Air filter. have been done few months back, I am thinking coil packs, I believe they are orginal on this car. Any idea's what u guys think would apperiated.

Thanks.