Audi Repair: Audi A4 misfires, vacuum leaks, vacuum hoses

Question
Hi Greg,
I'm getting 4 engine fault codes on my 2000, A4 1.8T petrol.
They are 16687,17956,17536,16684. When I looked them up they relate to misfires and the boot pressure control vale being open. Does this part need to be replaced? Also I have read that it could be the MAF sensor? Is this correct? Could this sensor cause the above codes? Is it expensive and easy to replace or is it a dealer job?
Regards
Ronan

Answer
HI
16687 and 16684 it is misfire. I will not worry about them
17536 it is for system too lean, it is posible that your MAF sensor is going bad but there may be some broken vacuum hoses. Take a very close look at all hoses connected to intake manifold, if you see any broken ones - replace it. I don't know how did you get these faults out. If you have VAG scaner you can look in value blocks , channel 32. the first and second reding have to be close to eachather if the first one is high you have vacuum leaks , if the second is high your MAF is bad. That's what I will do first and than reset faults.
good luck    GREG