Saab engine running issue
 

My g/f has an '05 Saab 92x (Saabaru). It's making an interesting noise, kind of like a quiet 'sneeze' with an almost imperceptible lapse in power. If I turn on the air conditioner, it happens about 1s later, and at random ever 10s to 60s thereafter. It doesn't seem to do it with the A/C off, but it's almost 100 today, and I didn't feel like fully vetting that theory.

My guess is a coil pack is going out, although I don't know much about these engines.

Thoughts?

Just a shot in the dark. With some Mercedes-Benz products, when the freon charge is low in the system the evaporator makes a hissing noise due to the low charge. Same kind of noise I've experienced with my MB's.

I'll check that - thanks!

is it just the compressor kicking in? I will listen to my car carefully tomorrow and let you know.

Could be. I topped off the refrigerant this afternoon; it was just barely in the 'filled' zone, but the A/C was blowing cold already.

That is normal on my WRX when the AC cycles on. There is a thermal switch that keeps the evaporator at 35 deg minimum and it cycles and you feel it. With 2 liters not under boost the AC is a sizable percentage of the engine load.