This is on my old bike which is now getting ridden regularly. It is a 7 year old bike that has alot of miles on it and I've never really taken the freewheel apart, but if someone coasts down a hill for a while on it, and tries to pedal the freewheel won't engage until it gets kicked or the bike gets bounced. Is there any way to fix this? I still have quite a few more problems that I need to ask.
Supcom is right. Try to find a lube called "Speed Skate Lube"; just as the name implies it's used on inline skate wheels. This stuff is great, you just use the spray nozzle (tube) and hose it into the freewheel while spinning it at a casual speed laying face (gears) up so the it doesn't drip out for about 30 seconds; then keep spinning the wheel for about 5 minutes after that, let it dry for about 12 hours then ride and see what happens. If it doesn't work then you need to replace the freewheel.
But the Speed Skate Lube works on all kinds of things, hinge sqeaks, chains, pivot points on various bike parts, wheel bearings (not car) etc.