? On a 1997 Nissan maxima

[Railroader]

I'm looking at a 1997 Nissan Maxima for a friend and his a/c cools a little bit, gets to about 76° at idle. Hooked up gauges and pressures looked ok to me no flutter or anything. Low side pressure was about 50° and high side pressure was about 300psi and ambient outside temp was about 118°. Gotta love Arizona summers. When you put your hand on the low side hose going into the evaporator it will get cold then get warm. I'm thinking it is a faulty expansion valve. Any ideas would be appreciated.
Thanks

[GM Tech]

Number one failure mode of mobile a/c is lack of cooling due to loss of refrigerant-- 65% of what I see has lost some refrigerant-- so start there- always- remove and weigh refrigerant- compare to under hood sticker- chances are good you have half a charge or less-- then evacuate system-pulling a vacuum- and weigh in exact amount of factory specified charge-- now does it cool any better? If there was a loss of refrigerant, you need to find and fix the leak- simple as that.

[Railroader]

Would the low refrigerant cause the low side line that goes to the evaporator to get cold the then warm. At the same time if the expansion valve if faulty and the bulb gives false readings that that would affect and/or could create that cold/warm affect on that low side hose. I think I will have him come over and vacuum the system down and weigh it back in