Do a search for the TFI module
by far the most common reason for no spark condition on the 2.9L EFI
TFI module is the ignition module, it is located n the back of the distributor using the dist as a heat sink LOL
They are problematic enough to make 2.9L owners carry a spare TFI module and the thumb wrench required to change it in the glovebox....
Also check the ECM fuse, make sure your computer is powering up, the fuel pumps are priming and sensors/injectors are getting power
It could be a simple ground issue
When the trucks get this old, the wiring also becomes suspect
BUT
if you have no spark at all 6 cyl the first suspect on the 2.9L is the TFI module
Timing:
on your EFI engine the computer controls timing, this means it advanced/retards the timing as it see's fit. This means if you try to set the timing without removing the computers control over it, the computer will simply compensate for any turning of the distributor you do. So Ford has provided you with a simple wiring jumper that you can remove to take the computers control of the timing away. It is called the Timing PIL.
To set base timing on the 2.9L you warm the engine up to a steady idle, then pull the timing PIL, hook up timing light to cyl #1, then rotate the distributor to get your base timing set.. re- install the pill and all is golden
I believe I had my 2.9L at 18 degrees BTDC, because here in CO (high elev) I could get away with it...14-16 should be good for performance minded sea level folks