Fuel pressure question NOT camaro specific

The info:

sbc 350, mechanical fuel pump (Holly or Edelbrock cant remember for sure but I know it was a good one when I bought it good flow and such), Inline filter, no return line, and an inline fuel gauge on the fuel rail (Mr. Gasket)

The Problem:

When i first fire it up i would have good fuel pressure on the gauge 7-9psi. as i let the car sit there and run the pressure begins to drop. After 10 mins or so it will read 1psi or less. I can rev the throttle and the pressure does not fluctuate. I'm wondering if for some reason this is a common issue/problem. Is it just the gauge, or could it be a pump issue. I'm wondering since I am thinking of installing nitrous this summer and I know consistent fuel pressure and flow is a big deal. Any help would be great.

Try a different gauge first...could be a bad gauge but could be something wrong with the pump too diaphram going bad.

I would upgrade to an electric pump and upgrade the fuel system before the nitrous

well the pump is 3 years old now I think. I was thinking about upgrading to electric but when I bought the pump I planned to run a plate style nitrous system with it and everyone I talked to (a very smart man who did the block work/ summit tech support) told me that should be plenty of pump to run with nitrous. I'm thinking a new gauge is what I need to do first. Any recommendations on a brand or style. Could I just swap another one into the fuel rail, or is there a better way of hooking one up?

its foolish to run nitrous on a mchanical pump.

At least put a pressure safety switch on it.


You can use any old gauge to check it