Hey People, I have a 97 Subaru Forester, my problem is that 10 minutes after starting it starts to drop rev's and loses power and starts coughing black smoke while im driving, I have to rev it hard out for a while to stop the problem. It is a intermittent fault, I have taken it to our local Subaru dealer and work shop and they have found no engine codes or boost leaks, I have change the fuel to 98 high octane, they also suggested it could be the pod filter, which I have changed to a K & N filter and still the problem happens. Can some one please help a fellow Subaru lover, regards 7Deuce