If your A/C isn't running very cold, there could be many reasons. First I would check the pressures. On a hot day, you should see at least 200psi on the high side and between 20-40 on the low side. If that is all good, and it still doesn't run too well then look at the condencer (in front or radiator) and check the temprature between the inlet and outlet, there should be a significant differece in temprature, and also, very overlooded, be sure the the line doesn't get cold until after the orifice tube. Ford condencers and evaporators can clogg easy, and so can the orifice tube. Dirt can clogg or just restrict any of these and although it may run and cool, it won't quite do the job.