V8 6.0 liter start problems

I own a 2000 GMC Sierra with a 6.0 liter V8. It will hesitate when starting and once started will rev to 1000 and then nearly stall out unless you give it some gas. I have already replaced the fuel pump and filter. Any suggestions?

Sounds like you arn't getting enough fuel, try running some kind of cleaner through the fuel lines and throttle body.