no start

well here is the deal i left my kids dvd player plugged in all night went out next day no start ,so i got it jumped seemed to work good drove around for a few hours doing things got home let it sit for a few hours then it woulnd start .so i replaced both batteries had the alt checked it was good replaced the cap, roter, wires and ignition module still no start unless you jump it has new fule pump and filter it is the vortec 5.7 and it has 117k on the moter.but whats real odd is you can jump it go drive around let it sit for a bit and it will start noproblem unless it is longer than a few hour it will crank but their will be no start.and then it will start some times.sorry it so long thanks for any help.hate to get rid of such a nice suv.:banghead:

Is it possible that the is a large build up of corrosion on the battery cables?Check the grounds for security and cleanliness.These are the easiest and quickest checks to make.I hope this will help.
Chuck's

well here is the deal i left my kids dvd player plugged in all night went out next day no start ,so i got it jumped seemed to work good drove around for a few hours doing things got home let it sit for a few hours then it woulnd start .so i replaced both batteries had the alt checked it was good replaced the cap, roter, wires and ignition module still no start unless you jump it has new fule pump and filter it is the vortec 5.7 and it has 117k on the moter.but whats real odd is you can jump it go drive around let it sit for a bit and it will start noproblem unless it is longer than a few hour it will crank but their will be no start.and then it will start some times.sorry it so long thanks for any help.hate to get rid of such a nice suv.:banghead:

As always on a no start check for fire and fuel and proper fuel pressure.

Hard to start cold.
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.
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.
Post back fuel pressure readings.

MT

yeah its the ignition switch.if i rock the key back and fourth till the service 4X4 light gomes on it starts up noproblem.