ok, my car has over 160K, 93 sentra se-r. when im driving and going around 20-40mph and have the car starts hesitating. like small losses and bursts of speed. and my foot is stationary on the pedal. Ive run through 1/4 tank of 92 oct and a bottle of fuel injector cleaner, but havent felt a difference yet, could i have a bad injector of maybe my fuel pump is going bad. or have i not given the fuel injector cleaner enough time. should i drive casually or drive it at WOT, can anybody help me?