if you have 30 psi at any point, the distributor is seated. When you have "0" psi at all times, that is the point I would look for that problem. Does it come back to 30 when you take it out of gear, what is the difference between hot and cold? How old is your gauge? try another gauge. How old is the engine/how many miles, does it smoke? could this just be an old worn out engine? How long have you had this engine? Is this a recent problem? Come on man, we needs details.....It certainly sounds like time for a rebuild to me, at least adjust shims if you have them, maybe a new oil pump. you need to get in there and see what is up.
