Correct Stock LT1 Fuel pressure?

I think my fuel pump is taking a crap on me. I put a fuel pressure gauge on it today and it read 35psi idle, and when i brought it upto 2K rpm, it jumped to 40psi and then fell to 30psi right away while i was still on the gas.

Car acts like its running outa fuel after 4.5Krpm but datamaster and plugs tell me its not lean at all. Car loses alot of power in upper and acts like its hitting rev limiter at 6Krpm, when its set to 6.5k rpm.


Fuel pump? Its still stock with 80K miles on the clock.

Put the pressure gauge on it, start it up and let it idle. Remove the vacuum compensation line from the fuel pressure regulator (cover the end of the line so there's no vacuum leak). Fuel pressure without the vacuum line should be 43.5psi. Factory specs are 41-47psi.

Reconnect the vacuum line, and the fuel pressure should drop in proportion to intake manifold vacuum. With a stock cam, a drop of 6-8psi from the "no vacuum" pressure is normal. With the HOT cam it might only drop 5psi. So, 35psi at idle, with the vacuum line on may be almost "normal".

Tape the gauge to the window, and take it out on the road. Run it up to max load/RPM. The fuel pressure should stay at 40psi or higher. Anything less and the pump is weak.

K thanks! Sounds like i need a new pump, but i needed an upgrade for the spray anyways, so i'm not out anything i wouldn't have been getting anyways.

Just was hoping this was also going to fix my top end power loss. I need to beat a Supercharged mustang later this summer :)