[brucepick]

I just cleaned my EGR passages this past weekend. 2000 Insight. No more herky-jerky. So far no visible mpg improvement, but the change from lean burn back to regular is a lot smoother now.

It had about 1-2 mm. thick tar-like black goop coated on some of the passage walls. Do you guys usually find it caked on nearly rock-hard, or more like a thick tar? I've been running Marvel Mystery Oil in my fuel (4 oz per 10 gallons fuel) so I'm wondering if that made my buildup any softer than usual.

I also found the steel vacuum tube going up through intake manifold was badly rusted - and leaking. It provides vacuum to the fuel pressure regulator. Spraying some carb cleaner on the steel tube while idling caused the rpms to go up and down. Finger-tracing the tube down under the manifold, I found the hose it connects to - so I plan to splice in a hose soon, to bypass the leaky tube.