[MT-2500]

Pressure is low.
But with a Airtex pump you are luckie to have any pressure.
Key on you should have 65 lbs with no fast leak downs.
Fast leak down can be fuel pressure regulator leaking or fuel pump check valve not holding or a leaking line.

Hook you gauge direct on to the inline at fuel filter.
Check for full pressure of 95-105 lbs and no fast leak down there.
Just do not run pump at full pressure over a few seconds.
Just long enought for test.

Here is guide lines for feul pump and pressure test.

The only true test on a fuel pump is to check the direct fuel pressure from fuel pump.
A quick test is to block off the return line and see if fuel pressure comes up to over 75-85 lbs.

Specs is 95-100 full pressure on yours and running pressure is 60/66 at fuel rail.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold and fuel pressure testing guide line.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be over 75-85 or more and up to 95-105.
And if it has a fast leak down after shut off you have a leak in system.
Post back fuel pressure readings.