Hello... This is my first post... So go easy on me.. I've searched the thread, yet still haven't find my answer. I have a 1998 Legacy 2.5 for some reason my car tend to idle really low at around 350-400. Is that normal? I remember the car used to idle around 800. My car has 67,000 km could it be time for a tune up? But I just got my engine rebuilt a year ago. I'm lost now. Please help this helpless noobie... Thanks..

oh yea... What's the correct way to reprogam ECU? Maybe that will help...Thanks again..

Disconnect the negative battery cable for both problems. This resets the on board computer. Time seems to very. I've been told from 5 minutes all the way to and hour.

ermn, mine idles @ 250-300 or so most of the time. I never thought that would be a problem, though if it is I suppose that would explain a couple of my stalls.

FYI, the tachometer starts at 500rpm, so your car is running at 600-700rpm, which is perfectly fine.

my car had this problem and it turned out that my o2 sensor was shot or it maybe your mass airflowsensor

... or it maybe your mass airflowsensor...
Try cleaning out the Idle-Air-Control Valve. If its gunked up, you'll have idle problems.