The strength of your battery, and starter, as well as their cables and connections, and even the viscosity of your oil will all affect your range of readings. Also the ring end gaps are smaller warm. The test can revile a fault such as a cracked valve, bad head gasket or a bad cylinder. If the reading rises significantly after adding a small amount of oil to the cylinder, it can be presumed that the (compression loss), was largely past the piston. It's the difference between the readings that gives the most important information.

 

I wheeling recently, decided to check the oil the other day and the dip stick was pushed out. I am assuming this would be cause by crankcase pressure build up, but what would be the most likely cause to look at?

 

The front tube from the valve cover to the air cleaner should be free to flow.

Maybe there?

 

Normal numbers for a 4.0 should be 120 to 150 no less then 30 psi per cylinder