Mate my 300 was doing the same. Oil pressure ok then drops to 0. Found out it was the Oil sender unit. Thro dealer wanted $285. Thro VDO cost me $70 plus $3 for adaptor. The part you want is a VDO Oil pressure Sender unit 360.005 avail from Cairns Instruments 740511849 and the adaptor to suit a 300ZX.
But this one also has the issue of running like crap when the pressure drops to zero. I would expect that the actual pressure is dropping out, rather than just the gauge. The sensor is also available from Repco for about the same price, but with the correct thread. The part number is in the tech section somewhere.
pressure is always between 2-4 now. will be doing a few fast changes, and if the problem continues I will pull the sump. The issue was not a huge one, its something that happened after over 1 hour driving in traffic, and resulted in minor power loss and slight detonation.
ok .. reading this thread i am just after clarification as my stock guage has started reading 0 on idle and comes with a tick (lifter related im assuming) which then goes away after 5-10 minutes driving or a hard kick. the car still runs fine and idles comfortably from 650-850 area. when the revs get above 2000rpm the guage then picks up to just below 2. on cold start up it sits up between 2 and 4 for a while. So i am just assuming that in my case, the car does not have a problem other hten perhaps the stock sender guage being a prick ?
Nemz could you please update this with what you did and what you experienced etc. There is another member with a similar problem.
Mine does the same (without the lifter tick) except on cold start it will sit between 4 and 6 for a while.
