How does it do when you rev it? How long has it been doing this?
You could have a blockage in the pickup tube or a broken pressure bypass spring in the adapter. There could be just that much wear in the bearings. What about your balance shaft? Is it still in? Heck, you may be as unlucky as I was and have a spun cam bearing.
Whatever the problem is, 6-7 PSI is well below the recommended minimum pressure. I would say don't run it until you get the pressure issue figured out.