hi new to the forum bought an audi a4 1.8t a month ago and whilst driving the car between 3000rpm and 4000rpm the car judders and pops worse when cold its realy winding me up can anyone help i put a thought code reader on it and had 9stored codes so i wipped them went out for a drive then 5 came back up they are 01247 00635 01262 16486 and 16518