Can any one tell me what the correct cylinder compression should be on a 1999 Ranger 3.0

 

No, because there isn't one...................

A compression test has too many "tester" variables for the manufacturer or anyone else to put out a specific number.
Engine temp
battery charge(starter motor speed)
intake open or closed
Gauge
all spark plugs removed(changes starter speed)

On any vehicle with a gas engine you should expect 150 to 180psi

But the point of a compression test is to test all cylinders at the same time, so variables are all the same, and then compare the numbers, they should all be within 10% of each other.

Higher compression is not always good, could be carbon build up.
Lower compression 120psi and down is never good.

3.0l has a 9.3:1 ratio, this is about the top for using regular gasoline, 87 octane, 3.0l like the 2.3l(9.2:1 and 9.4:1) would start pinging if fuel mix or EGR system was not perfect.

All that being said a new 3.0l should show about 175psi with perfect test parameters

 

Thank you Ron. I'm getting ready to do the test and wanted to know what to look for.
I'm all set.