Hey I just bought'74 240d and really look forward to learning more about diesels. The car seems to drive fine but the RPM's are a bit jumpy at idle. It does this while driving sometimes also but is less noticable when in gear. When it's iding and the rpm's are going up and down sometimes it will stick at the higher rpm and belch out all types of smoke and sounds. I plan on doing a fuel purge this weekend. Do those tend to help smoothe out some fuel system bumps?

Thanks much and cheers,
George