Low oil pressure when idle

[mtmacdaddy]

I own a '96 GMC 4.3l Sierra with about 120k miles. When sitting idle my gauge shows little to no oil pressure at all. When I give it some gas then the pressure shoots up to about mid-point and lowers down to about 1/4 total when on the freeway. Is this something to be worried about? It burns a little oil but there are no leaks and no engine noise. It runs great. I just don't want to do any damage to it! Any help is appreciated!

[bvanemon]

I have a 93 GMC my neigbhor has a 94 , both with the 4.3, both are well over the 135,000 mark. His was doing the same thing so I tested pressure with a mechanical gauge. It fell well within the normal range, I replaced the sending unit still the same thing, so I would assume that the dash gauge was or is at fault. Still a mechanical gauge is the best way to make sure.

[hypersport190]

My '94 has over 150,000 on it and the 5.0L engine. It also acts the same way. I have no leaks and burn a little oil and would say it is normal.

[mtmacdaddy]

dash gauge heh? I replaced the sending unit and that was not the problem so I will try the mechanical gauge and see what I get. Thanks!