A buddy of mine had persistent misfires on his Taurus. Compression test showed two weak cylinders. He pulled the head and laid it on it's side. Filled the ports with water after a few minutes a tiny dribble out of one valve. 1 of 6 intake valves. DOHC Ford. Then exhaust side . Two valves with little dribbles after a few minutes. Are these little dribbles enough to cause the misfire and low compression? The engine has around 150,000 miles. Is this just normal wear??