Real hard starting, like 2 mins cranking

I have a 5.7 engine with 242,000 miles that I bought new. I have only replace the head gasket and a fuel regular, nothing else on the engine. The engine has always started and ran well. The other day I started it and noted a slight miss in it at first (cold in drive way). After driving 2 miles down the road the miss or engine cuting out got much worst for the next 3 miles and then when i got on the freeway it went away. Now after sitting for 3 days I had to turn the engine over for 2 minunites for it to run with out the starter being used. When i first tried to start it would hit one 1 or 2, the not fire untill it got back to the 1 or 2 it hit on. I then held the started and the more the engine turned over the more cyclinder started firing untill it would run on it own. After warming it up I drove it 25 miles home ok. I then restarted it up in the drive way and it started right up and ran normal. I will check the fuel pressure in the AM. Any other ideas on thing that I can check that would cause this problem? Thanks Dave

Give us the fuel pressure readings.
Key on prime up?
Engine cold cranking?
Engune running?
And the engine running on road 30 minutes?

Thanks, Just went out a did a AM cold start (62 degrees). It started normal and idled with out a miss. Put the pressure gage on and it read 55 PSI with out the engine running, 54 PSI with engine running. I can hear the fuel pump (I replaced 2 so far) running for 5 sec with just the key on (motor not running) the it stops and will not come back on till the engine starts. I was low on oil by 2 quarts, just at the bottom of stick. Thanks Again, Dave

First thing you need to check cold engine cranking pressure.
And always check it when it is acting up.
What year and engine code?
Watch for fast leak off on engine prime up.

What brand of fuel pimps are you using?
If Airtex drop them in the trash can and get a good OEM type delphi fuel pump.

And give up all your fuel pump pressure readings.

Like this.

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 75-85 lbs.
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 or hot and fuel pressure testing guide lines.
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 75-85 or more.
And if it has a fast leak down after shut off you have a leak in system.
Post back fuel pressure readings.