Denny's right on the money, I would suspect it's a stuck expansion valve, It does concern me that you said you did not add oil as most compressors are shipped with out oil in them. Your low side is positiveley too low, but the high side doesn't seem outa reason as with R134a with temps in the 90's I usually see about 40 on the low side and around 250 on the high side as an average at idle speed. rule of thumb on the oil is 2oz for evap. 2 oz for condensor,1 oz for hoses, and then the compressor will need whatever the compressor manufaturer calls for. Either way I would first put a new expansion valve on it, I say expansion valve instead of orfice tube because all of those units I've seen use an xvalve....