Watch your coolant levels. Remove your radiator cap and look inside. READ the "dexcoolsettlement.com" web-site. Also, read the "GM Litigation" web-sites. You may be leaking coolant into the combustion chambers due to an internal coolant leak where the water "bridges" across the intake manifold. It is a design flaw, if this is the problem. What do your OTHER cylinders have for compression?? Was your engine EVER over-heated to cause a head gasket leak??? Good luck!!