While in gear and fully warmed up (4EAT), it's idling around 550. Oil pressure at this speed is around 5 psi. If the alt gets a demand, like say heater on and set to defrost only, idle kicks up to around 650 and oil pressure is around 10-12 psi. Is that low idle normal? 

no, should be around 700, +/- a few 10s, fully warmed up, in gear, foot on the brake.

going by the gauge, or a digital meter? low idle is fine, subarus idle fairly low, as long as it is not stalling, and the idle kicks up if you put load on it.

You can adjust the initial idle by clocking the IACV if you think it is too low. Sounds normal if it kicks up with load vs stalling. The mark on the tacho will look to be about 500 based on the graduations.

 

AT's do call for a higher initial idle than an MT. it should be displayed on the emissions sticker under the hood

I'm going off the dash gauge. It's been idling (when fully warm) a tick above the 500 rpm half-way mark when in drive, so figuring 550, maybe 575. It has yet to stall, and technically it's probably getting better fuel mileage at idle, but I'd like the oil pressure to be higher when it's idling w/o accessories on. It consistently kicks up w/o issues though when the alt is placing the higher demand. No idea WHY selecting front defrost vent with heater on puts a higher demand on the alternator though (selecting front defrost vent and low foot area vent doesn't for example), but with it on the rpms are 650-700 actually and that oil pressure makes me feel more confident.

 

Where is the IACV? Is it on the throttle body, or in between a hose? When you say clocking it, does it have a set screw you loosen, then clock until rpm is desired, then tighten? Clockwise or counterclockwise? 

 

SO glad I bought this car. Was idling the Saab earlier today since it's been sitting and about 5 minutes in it started knocking real loud under the timing cover, which I think means one of the timing guides busted and they are royally a PITFA to get at with the engine in the car Thankfully have a full timing kit (about $900 worth of parts as you have to do the balance chain and guides too- no $100 Subie kit here unfortunately) for it already. SO wish it was as easy of a job as the ej22 was. Could do an ej22 belt weekly and not dread it. But doing a T5 2.0L transversely mounted once every 170+ miles is not something to look forward too.

The ecu knows when the car is in gear or neutral/park to kick theidle up when there is load form the trans, then lets it down while in park. this is normal operation what you describe. The defroster ven, when the ac is working, engages the compressor to dehumidfy, creating load on the engine.

 

the IACV sits off the side of the throttle body/intake with the fat hose running under the intake tube to near the airbox. there are 2 screws on top with slotted holes, you can turn it one way or the other. I would only screw with it if the car is stumbling or stalling. I suppose you can play with it just to learn your car. Be careful not to strip the screws. perhaps crack them loose with a flat jaw vise grip. Take the unit off, if necessary, to accomplish this.

I wouldn't mess with the IACV adjustment.

If the idle is low clean the IACV, clean the throttle plate and bore, and make sure there are no loose vacuum hoses, then Seafoam. If nothing else its fun to watch the smoke.