1990 Pontiac Bonneville Repair questions?

[Simply_Wisdom]

I have a 1990 Pontiac Bonneville that has sat for over 12 months and I'm trying to get it started. On the latest repair, it stayed running as long as the air intake on the throttle body was covered, but died as soon as my friend took his hand off of that. The parts that have already been replaced so far include, alternator, starter, battery, ignition coil, spark plugs, and spark plug wires. All parts have been replaced with brand new parts and the car doesn't have engine or transmission problems. We tested all the fuel injectors and the fuel pump output is 42 psi. All the relays tested @ the same resistance as a brand new one bought from the store and so we left those in place. We replaced the engine control computer with a new one, but the new computer completely shut the car down, where as the old one allowed it to crank, so the old computer was reinstalled. So here we are, having tested and or replaced nearly every part of the fuel injection system and the car still won't stay running. What could it possibly be?