Set fan on speed 4, roll all the windows down, then turn on A/C and measure. If it keeps cycling on and off, and you see the pressure jump and drop, then you are probably low. Add just about 1/2 can of freon, then re-check the A/C gauges. Ideally, you want to check at 70 degrees F, but a "warm" day will do. You want to make sure that the pressure holds at a steady 30ish p.s.i. Bleeding the A/C is not the best idea b/c you'll also let out oil from the system, and you have to drain out all the oil, then refill to make sure the system has the proper amount of oil. Too much or too little oil can damage or ruin the compressor. With the A/C off, you'll get a high reading, like around 70-90. During normal operation, you should get a stable 25-35, ideally around 30. Hope this helps. Good luck! And by the way, while R-134a WON'T deplete the ozone layer, it is still a greenhouse gas. I've also noticed that many R-134a systems have a "sweet spot". Too little refrigerant and it obviously won't cool at full performance, but once you start to overcharge the system, the cooling capacity drops as well. Again, at 30 psi you should be pretty close to the "sweet spot".
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'94 854 N/A.