92 Subaru SVX with climate control issue

[darkrecess]

Hello all,

Some may remember me from the electrical issues I had previously had.

A little more history about my SVX, first.

The previous owner found it with the body wrecked and rusted out, and spent the time and money to restore it. She traded it in because she had been forced to go on disability, and was no longer able to comfortably get in and out of the car.

We just replaced the alternator in it (and haven't had an issue from it since). We are getting ready to replace the knock sensors, as well as the coolant temperature sensor.

At the moment, however, we have noticed that the engine will sputter and drop RPM's at idle (goes from ~900 to ~5-600 rpm's in park) when you press either the Econ or Vent buttons on climate control system. It will also randomly sputter while driving, sometimes idling at lights, othertimes it will sputter or surge while accelerating or cruising. (Some of this we believe the replacement of the knock sensors may fix, but my wife and I fear there is something else wrong as well).

Any idea what this is caused by?