2008 Vue XE: AC problem
 

I'm having the following problem with the AC. When I turn the AC on, the engine seems to struggle losing some power when accelerating and running a bit rough overall. When the AC is turned off, the engine runs smoothly. I've been told that it might be the AC compressor going bad but that it could also be the Alternator. How could I go about diagnosing this? I do have a bluetooth OBDII scanner but I don't know what to look for.

In my experience, most cats of that era and before we noticably affected by the horsepower robbing nature of AC systems. That being said, the PCM should be able to adjust the operating parameters to not run like a mess when the ac is on.

I would first check the ac high and low side pressure readings of the ac system while engaged to get an idea of the overall health/charge of your AC system. The result should point you in one of several directions. Please note the ambient temperature when you take the pressure readings.