Auto Air Conditioning & Heater Repair: 1998 Chevy Silverado Air Conditioning, chevy silverado, leak oil

Question
I replaced the evaporator case (only the cover)and the fuses are good.  It is blowing air but not as much as I think it should.  Also, as the air is blowing it cuts out and blows slower and then faster.  This doesn't happen all the time, but enough to be noticeable.

Also, someone told me that you have to put in three ozs of oil in the low pressure side?  Is this true?

Answer
Hi Juanita,

 When you had the evaporator case did you inspect the evaporator core for any restriction of airflow?  It is quite common that the core starts to leak, oil exudes out of the leak and catches dust and pollen from the air.
 Also, does the fan speed work on all speeds?  

Wayne