Things you might want to look at,
If the pump is mounted above the fuel level in the tank and the pump is dry/not primed this is a common problem, assuming the tank is front mounted. I have this problem also on my Malibu, but only the first time i start it, usually by the time i have spun the motor over to get the oil pressue up mine is ready to start,after that it fires right up, until next week.
Another source of problems is if the butterfly shafts are loose or have some play in the injection shaft bores it will suck too much air and make it almost impossible to start without priming the injectors. The only cure here is to bush the shaft bores or cut o'ring grooves in the shaft and install o'ring around the shaft between the butterflys, i've done this before.
Hope this helps.
Zip.