Rough start on my 6.0

[Jeffprenger]

Hi I have a 01 gmc with a 6.0 in it, recently I've been having hard starts. The truck starts fine in the morning when it is cold. How ever when I start the truck up after it has been running for some time it won't fire it will stumble on it's face and Barley run. To about 500 rpm them dips up and down to about 100 rpm them can eventually die off and will have to re start.

I have replaced the fuel filter last week and there are no leaks in the fuel system.

The fuel pressure off the rail is at 52 when the ignition is turned on.

When at idle and starting it dips down to about 45psi and will surge around a little bit. Holds pressure when shut off will drop down 10psi but holds it.

 

Thanks for any options I can do it fix it.

Jeff prenger

[Adrian17]

Have you changed the spark plugs amd wires? You could even try and clean the MAF or the throttle body. My 6.0 started up rough but it wouldent low idle like yours. I changed the plugs and wires and it fixed the rough start and idle i had. It even seemed to pull harder when you give it throttle. Those could be some things to look into.