Volvo: C-70 Turbo runs rough / engine warning light on, volvo c 70, vacuum lines

Question
Hi, I have a Volvo C 70 Turbo convertible (2000) I am in France and the mechanic at the Volvo garage is unsure of what is causing the problem.  The car has gradually started running rough after the 75,000 Kilometers (46,600 MILES) check-up.  The light has come on after each check-up, within 1 day of leaving the Volvo garage.  They have never given me the codes and say that the computer needs to be reset.  After the last check-up, the car has begun to run rough.  It starts fine, and can rev up but while driving it will start to bog down, often when changing to a higher gear or climbing a hill.  The car is sitting at the Volvo garage and the mechanic is not familiar with this model and said he is not sure what is wrong and wants to order parts from the Netherlands (bobines – sorry I don’t know the translation) to start testing, this sounds like a costly testing process.  Any ideas would be greatly appreciated, thank-you.  Could this problem be related to the turbo, as I am driving shorter distances these days?

Answer
Jackie,
It sounds like you need a new shop. The first thing to do is read the codes and follow them. When the fault codes are cleared it runs well until the code returns, right? Many things cause a car to run rough, but the fault codes should led to something. I have seen many that post mis-fire codes and needs new coils and plugs. I don't know about the turbo itself, but maybe vacuum lines assocated with the turbo.