clogged filters,dirty coils condensers,evaporators
2 reasons for the system to cut out, low pressure, and high pressure. I am thinking you are experiencing low pressure and need to recharge your system.
high pressure vapor
The low pressure connection for your 1993 Jeep Cherokee air conditioning system is located on the top of the air conditioning compressor. There is a low pressure connection and a high pressure connection, both should be labeled.
Low and high pressure systems. Obviously if you have a Low pressure system the barometric pressure will get low. High pressure causes the barometric pressure to rise.
You are on the wrong port. Some fords have an extra port that the low side hose screws on but is a high side fitting. look for another port.
dirty coil
check condenser
evaporator
There are two schrader / port valves to the air conditioning system. One will be a high pressure and the other will be a low pressure. You need a certified mechanic to check and refill the system. You can not simply refill the system.
It is called high pressure for a good reason. The high pressure side can and will pump the refrigerant back into the can of refrigerant and explode in your hands. One more reason to let the professionals work on the air conditioning in your vehicle.
There are several causes for high fuel consumption in a diesel engine. These include a difference in the weight of the vehicle, increased usage of air conditioning, and a difference in tire pressure.
http://www.unicosystem.com/ This is a high velocity system, hopefully what you are looking for.