I got my car scanned at autozone a lil while ago and 2 codes popped up.one was the obvious o2 sensor code cause im catless but the other was i forgot the number but i know it started with 3.The dude said i was running too lean but he suggested that i just use fuel injector cleaner and i should be good.What exactly does this mean? I do notice subtle things such as funny idle sometimes and a slight hesitation when im at least 1/2 throttle sometimes.What can i do to correct my lean situation and any idea what could cause it?