1995 STS. MySTS AC system is at 40 PSI according to the guages hooked up to the low and hi sides. The Clutch will kick on and the compressor sounds fine while running. However, The Clutch will only stay engaged and running for 3-4 seconds and take approx 30 seconds between these cycles. The compressor is not staying on long enough to pump freon and cool the car. Any Ideas would be fine... Thanks a lot....

 

Your car is low on freon.

System pressure with the engine off should be very close to ambient temp.

With the engine running and compressor engaged the low side should be around 40psi and the high side should be in the low to mid 200's.

 

I had the same problem, found out mine was the wire connector to the compressor.