If the coolant or oil does not need frequent fill ups, I wonder if it is in fact the head gasket. Do yourself a favor, pull the plugs and check each cylinder with a small flashlight. If a cylinder looks nice and shiney, then coolant is present.

There is a distributer, of sorts. At least a cap and rotor. Before pulling off the cap, scribe each plug lead on the side of the distributer and then remove the cap and continue the scribe to the top of the metal so you can see where the rotor will match the scribe mark.

Remember, the firing order is 1,2,4,5,3 and #1 is at about 9 o'clock.

You also might want to pour a table spoon of oil into each cylinder if the engine is cold so that the rings will seal. Remember, if there is a bad plug on #2, the gasoline will wash off all of the oil and mess up the compression reading.

Did the owner replace the plug or just the coil? Spark plugs have been known to be bad.

Your ideal compression ratios should be 166 to 185 psi on a WARM turbo engine.
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