[Big hammer]

With the car parked rev up the motor and short out the plugs to see if you can find the clylinder thats missing. It's probably #1 with the tight vavle, remove the tight valve spring and with some polishing cloth polish the stem. Use some mmo or penetrating oil and spin the valve stem in place, I had a tight valve stem and was able to free it up some. I think I use a heavy rubber band wrapped around the stem twice spinning it like trying to start a fire caveman style. The more it run the better it got, any way might be worth a try. Don't tell anyone what I did when I didn't have much green stuff:-)
You might be able to slip a lengh of rubber fuel hose over the stem and spin the valve with a drill, with the spring off