OK, I searched and asked a question in a different thread but nothing was offered so I'm starting my own thread in an attempt to diagnose the problem.

I have a 96 4Runner with the 3.4 and if I have the AC on while driving I'm fine, no noise at all. BUT, if I am stopped for any length of time it will start to moan and become quite loud, much unlike my wife. I had this happen while driving through Mt. Airy, NC in town about a year or so ago and I stopped and one of the AC lines was vibrating. I can't remember which one but this ONLY happens when I stop or am rolling in rush hour at a snails pace. AC blows plenty cold, recent recharge and new evaporator so I'm clueless. The AC compressor and clutch don't make any noises either.

 

Is the noise coming from inside? Under the hood? Could be that something is vibrating when the engine is at idle speeds?

 

It's something with the AC itself whether a clog or whatever. The lines are tight and don't rattle so I'm totally stumped.