2005 Chevy Malibu Starting

I have a Malibu Classic 05 and it has a problem with starting. It is turning but it sounds like the gas cant get to it to make it crank. Sometimes it cranks right up an somtimes it takes 45 minutes to crank. I have taken it to two different shops. The first time they told me I needed an injection switch and then they said a fuel pump and fuel filter. Next I took it to a different shop he said maybe the fuel pump was defected so I used the warranty on it and got another one and he put it on and it is still doing the seme thing. He has put it on several machines and it passes everything. Same thing the last guy said to. What areas could this be? What are some possibabiltes?