i have a 87 4000 5cy non turbo. heres my problem when its cold outside the car runs bad, really bad hessatation. i give it gas and it acts like it has no power. Doesn't stall but acts like something is holding it back. this only happens when its cold though. on nice days it runs fine. i'm putting a new o2 sensor in it tomorrow. any ideas of a good place to start? btw i'm a new audi tech so i'm clueless on this fuel injection.