Toyota Repair: A/C, mitsubishi galant, metal shavings

Question
Hi, I have a 2001 Mitsubishi Galant which I just purchased about a month ago.  The A/C isn't blowing that cold.  A mechanic looked at it quickly and put some R134a in it (since it was a little low) but it still isn't blowing that cold.  The other day for example, it was almost 80 degrees outside and the temperature at the center vent was mostly around 68 degrees.  There was a point where it was blowing at 56 degrees but it only stayed there for a couple of minutes and then went back to 68 degrees.  The other day it was 90 out and the A/C temp was about 77.  Today it was 60 out and the A/C temp was 44.  The A/C was always in recirculate mode and I heard the compressor kick-in every so often and the fan was set to speed 2.  When I set it to 3 or 4 the temperature would go up about 10 degrees (I guess because it was adding in warm air).  Also, the A/C temperature didn't change much when I was idling as compared to when I was driving.  Also, the low pressure line under the hood was ice cold.  Other cars that I have had had very cold A/C's.  Is it possible that this model car just doesn't blow as cold as other model cars?  I read on the Internet that sometimes metal shavings can partially block the line and divert the cold air.  Could this be the problem or do you have another suggestion?  Thank you for your time.

Answer
The temp at the vents should be at least 42 degrees or less, 48 would be acceptable, no matter what the outside temperature, there is a problem with this a/c system, it may still be low on freon or there may be a blockage. You should have good qualified a/c technician check this out, the line pressures should be checked using pressure gauges, that's the first step, this will give an indication of the general condition of the system and indicate where the problem may be.