Oil light
 

Hi, first time here.
My 1980 928 has started flashing the oil light under acceleration. Its been getting worse in the last day or two. Alright, changed the oil, new filter, all topped up and it still happens. It won't blink if I sit in neutral and rev it, but as soon as I pull away, the light blinks, and stops when I take my foot off. Could the pump be done, or is there some techy sending unit in the pan? Is it a low pressure warning light? The oil pressure gauge is totally unreliable. The car runs fine, doesn't burn oil, not hot....wtf?
Any input appreciated, Garry