Upon arrival customer stated that ac unit was not keeping up inside home and unit would constantly running all day. After inspection of 8 year old system, found that refrigerant pressures were very low showing 34/292. Did a leak search and did not see a leak present. Started system back up and found that the TXV metering device on the indoor coil has failed as is not metering the refrigerant properly staying stuck closed. As unit runs refrigerant pressures drop low to the point where indoor coil is freezing. Gave customer estimate for new TXV metering device. Do recommend speaking with install supervisor about updating system due to cost of repair, age of equipment and unit is out of warranty. System is not cooling properly at this time, advised customer that longer system runs the evaporator coil will freeze more. Will follow up with customer Monday morning about part availability supply house was closed.