Noticed on sunday that my defi oil pressure gauge was bouncing and not going up and down how it usually does. When i start up from cold it use to go staight to 4bar and now it stays at on 0bar for 4secs then goes up. When warm it usually sits just under 2bar but now its round 1bar. I pulled up in traffic yesterday and it dropped to 0bar and dash light came on as i saw that i was about to turn it straight off then all of a sudden the dash light went out and the needle went up on the gauge. This is starting to worry me ive spoke to my engine builder and he said to get a mechanical gauge to check the pressure. spoke to other people and they have said sticky oil pressure relise valve, pump, oil pick up and also my mate had a problem like this and it was down to a faulty oil filter. Can any one help or advise ?