Had two similar problems on my own vehicles recently, one a Hyundai Matrix CDI Diesel which either wouldn't start or if it did had no power, turned out to be the air control valve on the inlet manifold where the intercooler hose connects, it was simply full of oily crud and couldn't open properly if at all, a good clean cured that. The other problem was a recently acquired Volvo S40 (with Renault dci engine). Again no power or wouldn't rev, this time it was the EGR valve which was stuck closed, again a good clean sorted it out and no more problems with either since. Its worth noting that Hyundai wanted to fit new pump and injectors to the Matrix (£2500 on a car worth about a grand....) with no guarantee of a cure so watch out if you are getting quotes for repairs.
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August 2012
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