Look here:

http://www.brickboard.com

Look through the RWD faqs and tips.

There are many things to consider in you case, starting with  which fuel
injection system you have. The weakest link, coomon to all Bosch
systems, is the fuel injection combined relay. Secondly, if the car sits
a lot, the main fuel pump itself may be sticking and refusing to run.
Sometimes tapping on it while someone cranks the motor will initiate a
start. Beyond that the diagnostics are system specific and since you
haven't stated or determined which system you have post back when you
can relate that information.

Bob

It's worth noting that I have never seen an ECU that was bad except two that
got wet.

Mike

When you turn the ignition to the "ON" position, can you hear the fuel pump
running? You may need to get a helper to listen with his ear to the gas cap.
If the pump does not run, your first suspect is the fuel pump relay.  You
can try reflowing the solder joints, or simply buy a new relay. Otherwise,
the problem probably lies with your ECU.  They are famous for failing such
that they no longer (or only intermittently) ground the fuel pump relay and,
obviously, if the relay isn't grounded it isn't supplying power to the pump.