my oil pressure goes down while idleling but goes to normal when i drive it, what is causing this?

as you may notice the oil pressure will be at almost max when cold, untill the engine warms up and it starts dumping the excess pressure. low oil pressure at idle is a sign that the bearings are starting to get a little wore. its a typical chevy thing. if you want to keep your oil pressure up. run a heavier oil. I have a 97 chevy 350. i run 10W30 in the winter and 15W40 in the summer. aslong as you keep the bearings lubricated by adding a thicker oil. it will result in longer life of the motor. if you are running 5W30 switch to 10W30 and if its still got a little bit of an oil pressure issue throw some lucas at it. the point you should be concerned is when you see the oil light kick on.