Measuring compression with a Harbor Freight compression tester, (using injector holes) and after checking 2 cylinders in the 300's, started getting low 100's, and when i went back to the cylinders that had tested in the 300's, those too were now in the 100's. The release valve took several attempts before it would release the pressure. Any idea what's wrong? The engine starts on a dime, and seems to run smoothly, so i'm inclined to believe the 100+ readings are bogus.



Thanks!