1994 Lexus Ls 400 A/c Problem

[Larry W]

About a year ago I had a new compressor, clutch assembly, dryer & evaporator installed. The A/C never seemed "ice cold" like our 2001Toyota Avalon or our trusty 1999 Jeep Cherokee. Winter was starting so I did not use the A/C much. When the temperature started climbing here in South Florida I noticed the A/C air temp was colder coming out of the left side drivers vent and the center vents. The vent on the passenger side was noticeably warmer by a few degrees. I pulled the filter bracket out and realized the filter had been removed. Its definitly not cold at idle, but gets colder as I accelerate up to about 40-45 MPH. Am I just low on freon? My neighbor has A/C gauges to hook up. What should the gauges be reading for normal operation at idle?