THE air conditioning compressor on my 90 corvette shuts off after running a few seconds any ideas whats wrong?

The refrigerant level is probably low. When the compressor turns on it pulls refrigerant from the low side and as soon as the low side pressure drops below a certain point, the sensor disengages the AC clutch. If you haven't already converted your AC to 134A, now would be a good time. All vehicle AC compressors leak a little refrigerant, simply because of the design of the system. The system may not have any serious problems even though it has lost a little pressure.