I have a 94 Z28 with the auto trans. I replaced the starter a year ago, then bypassed the VATS, had no starter problems for a year and then the starter solenoid would randomly click but not engauge the starter. I replaced the starter and had no problems for a week or so. The new starter did the same thing. I exchanged the starter with an upgraded NEW starter, positive cable and battery. One week later it is doing it again. If I click the starter several times it has started the engine. I checked the battery ground cable and connection and they ohmed out at less than .5 ohms. I had the wife crank it over while I measured the voltage of the wires at the starter. The positive battery cable had 11.9vdc while the key was in the start position and the engine not cranking. At the same time the purple start wire only had 8.9vdc. This data was taken while holding the key in the start position and the starter failing to crank. I then jumped the starter from the psoitive cable to the purple wire with the key on and it started several times with no problem. I am now finding it difficult to acquire 1994 LT1/m4 diagrams to continue looking for the voltage drop to the solenoid. I can find the 1993 and 1995 but I am not sure it they are exactly the same. Any suggestions would be AWSOME and would make me a hero again...

 

others can prob contribute more, but two little things i've found on that year are : 1. corrosion on the wire junctions (under the red plastic cover pass side). 600 sandpaper and cleaned, put them back the same way.

2. the coil wire is prone to corrosion at the coil, check it and clean/replace

 

I'm pretty sure Shoebox's diagram for the 95 will work with your 94. Not sure about that "m4" though....

 

What about ignition switch? I had one go bad on me and it had similar symptoms.