My almost totally stock 93 LX 5 speed has oil pressure that never quite makes it to the middle mark while driving. Also, at stop lights, the needle will fall to the mark below middle, which if ur looking at the gauge, looks pretty low. Is this normal? The engine runs strong, no weird noises, no smoke. I use brand name 5W30 full synthetic every 3 thousand miles and i've only driven it about 6k since I bought it last summer. I'm not sure if this is a new thing or if I just never noticed this before. The car has 123k miles on it. Any thoughts?