Is this a recent change or has low pressure been happening at idle for a long time? I have owned my 88/5.7 for well over 15 years. After the oil heats up to temp and at idle, my oil pressure always zeros out, or very close to it. Every Chevy that I have ever owned has done this. Even those with just a light. At idle the light would flicker until I started up again. I never gave it a second thought
I have had the sending unit for the gauge fail all together. When that happens the needle doesn’t move at all. It doesn’t matter what weight oil I use either.
if this has been happening all along then I wouldn’t be concerned.

 

In the interest of discussion & debate, why do you think the loss of oil pressure is nothing to be concerned about?

Or are you meaning that the loss of the oil PSI gauge isn’t a concern?

 

Upon starting up, after 7 miles, it loses power and won't go over 30mph. It's a 1500 5.3 V8 2 wheel drive with throttle body. About 165K miles. Two different auto shop expensive scanners gave no codes. It does not sputter like a plugged up cat converter. Also has fresh gas. If it sits for a while it runs fine for another 7 miles then does same thing. It also idles smooth. All suggestions and ideas greatly appreciated. to solve this problem. Thanks for anyone's help. Denny

 

I’d recommend you start your own thread for this issue as it’s not the same problem as the OP.

 

Because what I said. In my case this condition was repeated many times. My pressure was high when the oil was cold. It stayed high when I was driving. It went down again after the oil heated up when I sat at a light or stop sign. If it was the pump you would get low or no oil pressure regardless of the rpm’s and oil temp. I would not have gotten very far if I kept driving all these vehicles with bad oil pumps. Is the engine making any noise due to a lack of oil in the top end. If the pump was broken the engine would sound like a bunch of marbles rolling around.