fasteddy,<P>The mechanic ran a "computer compression check". Apparently the diagnostic computer cuts out the cylinder sparks in turn, and measures the change in RPM (?). If the cylinder won't hold pressure, then there's no effect on the RPM, and the computer flags it as low.<BR>I think that's how it works...<P>All cylinders with good compression.<P>On the round trip to the Rubicon, I travelled more than 3,000 miles in a week and half (I think), and didn't even burn a liter of oil. I'm assuming the engine's good. Rebuilt 2 years ago, including cylinders bored, and new larger pistons.<P>But in the space of 3 days this week, it suddenly decided burned a liter...<P>Frustrated...<P>Don