cylinder compression

My 98 yukon 136k miles was diagnosed with a bad #5 cylinder. The reading came to be 90psi. Is it possible in any way that this could have been misdiagnosed? Is an engine rebuild or swap(remanufactured) the only way to solve this problem?

How misdiagnosed, what were the other cylinders, loosing coolant, is there a misfire, rough idle? Not much info here. This may be a valve issue, a leak down test would pinpoint the area of compression loss.

The lower intake gasket was replaced about 7 months ago. Amonth later i changed plugs, wires, rotor, distr cap, and the spider injector assembly. From what i was told he only checked 2 other cylinders and they were at 125 and 130. It has been loosing coolant but only have to add after maybe 45 days. yes their is a rough idle with a misfire.

As I said a leak down test will pinpoint the problem.

ok i called around and found a couple places that will do the test but it won't be til monday. What i want to get clarified is, with this test it will pinpoint wether it be intake valve, exhaust, or head but will it still need a rebuild or is it possible to correct this without a rebuild?