One thing that might cause that is,the injectors might not be working.
On that note we would check the fuse for the injectors and make sure power is getting to the injectors.

We will with the key on, have power to every injector or we won't. and if not determine why not.
The computer provides the ground and the injector injects and we need to make sure that is taking place..

 

where is the fuse for the injectors and how would you test the injectors

 

Because all vehicles are not the same, your best bet is to check in your owner's manual, If you can't do that, get a test light and with the key on , you shoild have power to every injector, most of the time, the RED wire that feed all the injectors.

The only way to be sure the injectors are injecting fuel is to remove any spark plug after it won't start and see if the plug is wet (getting fuel).