I had a similar situation with my 2000 silverado. I changed the plugs, and the gaps seemed to be off. After new plugs, Starts right up. Don't go too cheap on the plugs either. Hope this helps.
Sully

 

I have had the same problem. Once the engine starts there is no problem and it runs great. I have also checked my pressure after the truck has sat for overnight andI found the fuel rail is at 0 psi.I would thinkif thefuel system is tight the pressure would stay on the fuel rail after the engine is turned off. I have thought the fuel pump is allowing the pressure to bleed off back to the tank and it may need to be replaced but that is alot of work on a hunch. I also don't think the injectors are leaking because there is no indication of flooding.
May someone out there knows - should the pressure bleed off the fuel rail after the engine is turned off ?

 

chevytalk.org very knowledgable

 

i just recently experienced the "Hard Starting"on my '00 2500 (6.0). There has been a very annoying hesitation/no power situation from a dead stop acceleration. Mechanic found that the Fuel Pressure Regulator was bad (fuel in the vacuum line)which was overloading the engine with fuel. I still have a slight hesitation problem from initial acceleration, but it is no where near what it was. I may have a vacuum leak or a TPS problem.

 

The pressure should stay constant for a while then very slowly fall but not to zero. Look up the thread for "Scope' in silverado I explained how to test for where your pressure loss is

 

Change the fuel pressure regulator. if there is gas there when you pull off the vacuum hose, that's the problem. I promise. If it don't fix it, send your hate mail to my address:

1600 Pennsylvania Ave.
Washington, DC

Ask for Barry. Feel free to punch me in the face.

 

*Update*
I had the mechanic replace the fuel pressure regulator and still had the "Hesitation" from Off Idle. I tested all the sensors for continuity and the voltages at each wire. Nothing was showing up as bad. Eventually, I borrowed a MAF sensor from a buddies truck and "POW", it worked. No more hesitation and now it runs like a Chevy should....Yeah for our team.