My wife just got a F-250 5.0 EFI (302) 4X4 from her father. It drove home OK but now it will not start. It will crank and the fuel pump works. If I put gas into the intake it will start then die. There is power going to the injectors put they don't get the signal to open. Any ideas on what to check- This is the first Ford the we have owned.

 

There are two relays on the driver's side inner fender...they are in a little black box behind the windshield washer fluid reservoir. One is the fuel relay and the other is the ECC relay. I would try replacing those first...the corrode inside and stop making contact.