A 1994 Chevy Caprice which has lost all power has the ignition timing set incorrectly, bad spark plugs, or a dirty fuel filter. If all components in the engine do not work perfectly in sync, power and performance are easily lost.
What is the engine in the Caprice? In the Suburban? If they are a 305/350 then they can be interchanged. I have a 1985 Caprice Classic with a 305 and the tranny came out of a 1987 Suburban. It depends on the engine.
The problem when the digital dash of a 1994 Chevy Caprice goes out might be a fuse that is blown under the dashboard. This might also be related to a problem with the computer or with the wiring to the dash.