The Dang Truck Engine Again

[drbarbara]

what the guy told me was that the #7 cylinder was only compressing 25 lbs.

[spareparts]

need to do what is called a wet/dry compresion test. You check compreion on the cylinder as is. Then squirt some oil down the spark plug hole and recheck. If the compresion comes up big time, you've got ring problems, if it comes up just a little, or none at all, you have valve or head gasket problems. A leak down test would give you more clues.