Air shocks are high pressure, low volume. Air will escape in a split second with a standard pump or gauge. Whether a screw on or clamp on pump, both will allow too much air to escape. I find my RockShox rarely require air, but I had to purchase an air shock pump with gauge. If the bike didn't come with a fork manual, check the fork manufacturer's website.
Thx for reply and insight. I will stop in at my bike shop and let them wrestle with it. I tried to put air in but, as you say, it escaped as soon as I disconnected the pump.