i have a question with reference to oil pressure, if you have full oil pressure when car is cold then nothing once warmed up does this mean i have no oil pressure or does it mean the gadge is crap, and how much to correct this? please

The standard oil pressure sensor is notoriously unreliable when it gets old. They then give the symptoms you mention

However, so does engine wear. I'd get hold of a mechanical gauge and test your pressure with that.

As mentioned, the gauge is temperamental or more precisely the stock sender is probably dying. After all the gauge just displays what the sender is saying.. Most of us have gone for an aftermarket oil pressure gauge which uses a sender that's normally screwed into a sandwich plate on the oil filter hole.

 

Obviously, the oil pressure will reduce as the engine warms and the oil thins...

Buy and fit a new OEM sender. Job done.

Buy and fit a new OEM sender. Job done.

 

That's certainly an option but you can get an aftermarket gauge with a sender for less than the cost of the oem sender..