a/c not working at idle

when I'm idling in traffic, my air doesn't work, however once I get going it blows ice cold. any ideas? its a 98 EB 4.0 sohvc

Is the cooling fan working properly? If it is not, the condensor is not getting enough air flow at idle. This could cause your problem. If you do not have an electric cooling fan, look at the fan clutch or the water pump not circulating enough coolant at idle.

pretty sure the fan is working correctly, if I"m sitting at a light and put it in neutral and rev up the motor a little it also starts blowing cold air, so that doesn't seem to be indicitive of an airflow issue.

When you rev the engine, if the fan is attached to the engine, it is either an air flow problem or a weak water pump. As the engine increases speed, the fan will pull more air. Try using a water hose and spraying the radiator and condenser from the inside of the engine compartment. It may just be dirt and debris in the radiator or condensor not allowing it to work properly.