What exactly does trouble code 46 mean for a 1994 chevy caprice 5.7L (vats)....?

The fuel pump isn't being shut down , the engine computer isn't seeing a anti-theft system pass word (code) so it disables the fuel injectors . The security light on ? DTC'S - diagnostic trouble code's are stored . Need a factory or professional scanner to read this code's . You could try a by pass of the key an lock cylinder ,but that may not be the problem . Does your key have a resistor pellet on the side of the key >
GM VATS Key Resistor Key Security Bypass

Here's a video on your car. Bypass GM Vats Security

You shouldn't. Most remotes, hooked up properly, have a learn procedure that starts the car. It bypasses the vats system.

CODE 46 VECHICLE ANTI THEFT SYSTEM VATS, CODE 46 FRONT TO REAR BANK FUELING IMBALANCE.

Sounds like a bad wire connection. Check the connectors for cleanliness and that they are tight and free of corrosion.

that means that your fuel pressure isnt high enough to run check fuel pressure should be 40lbs on crank mode and little lower in run mode , you might check fuel filter

U have 2 seperate problems, the gas gauge issue is caused by a defective sending unit in the gas tank, the cutting out will require u take the car in and have the electronic engine control system tested for trouble codes. Does this car have the 5.7 L engine?

Only thing you can do yourself is to pull off the connector on the computer and check pins for corrosion. If you can get another computer on "loan" you might try plugging it in. though its somewhat rare (it should be) computers do fail. On older cars you can likely get a replacement in any scrap yard. sorry I can't help more, but with no readings, everything points to what I've said. You should also check ignition switch to amke sure power is coming out of there to remainder of system.

no not really