As part of a 200k mile check-up on my Protege5 I completed a leakdown test. Leakdown in all four cylinders was acceptable, less than 20%, but on 3 of the cylinders I could hear air leaking into the adjacent cylinder. I did not hear leakage into the intake or exhaust. Adding a little oil to the cylinder brought the leak down up into the 5-10% range. There were no bubbles into the coolant and the car has not been using coolant or oil. I've done several of these tests before but I've never heard air leaking into an adjacent cylinder. Is it time to pull the head and check it out?