Hi all,im desperate for some help/tips/advice. I stupidly asked my local unifit/kwikfit autocentre type establishment to change my oil & filter on my 02 a4 cab before embarking on a long journey. When i picked the car up it rattled like buggery,ran very lumpy & was generally terrible to drive. I took the car back & they said the cam position sensor was faulty. I wasnt happy for them to carry on so took the car to a friend of a friend who did a diagnostic for me. Several codes were stored including:17748 CAM POSITION SENSOR(G40) & ENGINE SPPED SENSOR(G28) UPPER LIMIT EXCEEDED MIL ON P1340-001. 16684- 16685-16686-16687 All relating to misfires being detected on cylinders 1,2 & 3. I rang the original centre to be fobbed off with some plug lead excuse. Is there any particular area i should be looking at? Could all these faults be linked to type of oil fastfit centre used? My audi is now resting in my drive whilst i commute in my fathers mitsubishi!! please please help me