gm 2400 vortec LP wont start unless I hold the accelerator down. When it does start it runs rough then quits.

I can smell fuel and the electronic throttle body is making a whining/buzzing noise.

Im thinking its getting to much fuel or to high of a fuel pressure, how do I go about testing fuel pressure and/or volume?

If there is anything else I should check please let me know.

Thanks.