ran a compression test after doing a valve adjustment the other day. my engine is only 9.6:1 since its still the stock b20z block, but anyway its not good.... 190-165-145-200. cant figure out what the problem is. oil and coolant both look ok. not smoking except a slight amount at high rpms. no soot on the bumper or even the tailpipe. plugs look fine. might be time to rebuild. or any chance it could be just the head gasket?