The other day I noticed my engine sounded just a tad louder than it usually is. Today I also noticed that when I have the break pressed fully like at a stop light I can feel more vibrations in the break.
This seems to have gone away pretty much the second I turned off my AC.
Anybody have any thoughts what could be the cause of such a thing and what the fix would be?

 

I had something similar with my Maxima a while back. Turned out the AC pulley wanted to pull off the compressor and go its own way. I'd check under the hood to make sure that the pulley isn't causing this.

 

Its just adding additional load on the engine. Just like in your home where your HVAC system will be on a breaker of its own, this is because it's the single largest consumer of electricity. This is usual for any vehicle, and it use to be that when you would turn on your A/C in your vehicle the computer would see this and raise the idle to compensate. Maybe your freon is High or Low and making the compressor become out of its efficiency range causing the engine to work harder to spin it. It could also be motor mounts but less likely on a newer generation car like ours. In the end it's not that big of deal to be honest, if your concern still continues just check those couple things I mentioned.

 

How many miles on the GS? May be time to look at motor mounts.

 

130k miles.
Thanks guys for the advice

 

After writing my comment yesterday I was more observant of my car driving around today and guess what?... Mine seems to do it as well. It appears to do it 30% of the time, with no clear pattern that I can perceive. I'll report back here if I come up with any kind reason or conclusion as to why this may be happening.