replaced the PCV valve yet? if you have so much blow-by that the oil fill cap has blown off, you are without a doubt also forcing oil out the seals including the front and rear main seals. either your piston rings are so worn out that you are scaring the cylinder walls, or your not recirculating the air that is in the crankcase. while the 1 cylinder is a lot lower than the other 3, I would not really expect that to be where your lack of power problem is, more likely the lack of vacuum through the PCV valve circuit, and the leak of vac through the air intake where the pcv should be hooked up.
when you say "the governor is working", can you describe a little more how you know it is working correctly?