[Pontiac1976]

Most idle factory truck/car warm would be 550-650 oil pressure will be low. The oil pressure should have a normal pressure reading and normal dropping pressure and a normal steady low end pressure when warm. *( for your own truck/car) If it running ok the parts that may be in the truck/car there lot of things that come in to play new oil, old oil. thick oil, thin oil. Miles on motor it helps to know your truck/car motor. how much metal in the oil normal or above normal lots of metal flakes. How new of a rebuild on motor a breaking motor will show a little more wear on break in fore the first 500miles. Take the coil wire off remove valve covers put some rags around heads turn truck/car over about 1-2 min or till you see oil pushing out the push rods at the rockers arms. oil come up the you got working pressure. Then you know getting oil up. So then if you tested gauge say good sending unit, oil, dirt in the old sending unit, or gauge. or if the oil dribbling out only maybe oil pump or dirt in the pump or pick up plugged or missing or pump wore out. How tight the motor build. To thick of oil will make you loose HP. Most new oils now a days are thinner and are synthetic. RPM will change Oil Pressure big time, If you rev up to 1000-1200 RPM you should see it go up a fair amount unless you pump failure ( same thing you do after oil change start up. To make sure oil get up and you have pressure. OIL viscosity when it starts to break down oil pressure will drop a little more and more at first once you know you oil normal temp where it sits before and after warm up idle and drive and RPM's you can see the viscosity break down check mile know when to change oil and this is for reg oil and synthetic oil because once viscosity breaks down it not lubing the motor well at all.