Sounds like the classic dirty/plugged filter. Do like Cavaliers6 said. I wouldn't worry about idling for an hour, though.

I replaced both filters. I filled the spin on filter with Sea Foam fuel injector cleaner before I put it back on. Then I dumped the rest of the bottle into the tank. I fired it up and idled it for about 10 minutes while I cleaned up where I was working and threw my trash away. Then I found a nice, quiet 1/4 mile straight away in an industrial area. It worked great for 0-60 runs. On the 4th or so run I put out a HUGE cloud of black smoke and it started picking up. By the 6th run the smoke had died down. Between the new filters and the Italian tune up it was running much better.

Give it a try, it should fix your problem. After that read up on the banjo bolt and how to clean it.

-Jim

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1995 S350D, Green with black leather interior.
Bought January 2008 w/ 233,xxx miles.
I did 22,000 miles during the first year of ownership.