Nissan Repair: misfire 1992 nissan maxima, nissan maxima, valve seals

Question
I have a misfire on #4 cyl all the time.  Compressions are 160 psi.  Car has new injector and connector [was corroded], new plugs, new wires-good spark so cap/rotor good.  Injector wiring good-has power and is switching.  No obvious air leaks at manifold.  O2's pass test with snap-on scanner tool.  Any help would be appreciated.

Answer
Jerry,

Check the oil consumption on the cylinder by pouring in a teaspoon of oil into the chamber and repeating the compression test.  If it rises by 10 psi or more the rings are gone on that cylinder.  If not then you are looking at valve guides for that cylinder.  In that case replace the valve seals and the problem should go away.