Hello, I'm am new to audiforums so i don't really know how this works. I have a 2003 audi a4 1.8T quattro and am experiencing a lag in the throttle. at points the acceleration is fine, at others its unbearable. My father is a mecchanic and says it could be the timing belt, but he can't find any issues with it. Also the check engine light has been on since i bought the car in May. Any suggestions? And is there anything i could do to give it more acceleration?