When doing a compression test, the important thing is the variance between the cylinders. This is why you won't find a specification for compression readings. You should see no more than 15% difference in psi between any cylinders. 10% is even better.
A reading of about 150 psi is about average for any stock 4 cycle engine. This is just an average, and the reading could be from 120 to 180 psi.
If you have a low reading on one cylinder, this would likely be a burned valve or worn rings. A low reading on adjacent cylinders represents a blown head gasket, leaking pressure between the cylinders. Low readings on all cylinders could mean the timing belt or chain is worn and skipped a tooth on the timing gears.
