For roughly two years, I have had this pesky code on my car. I tried cleaning this and that, changed plugs and wires to no avail. this weekend, on my way to Syracuse, the car suddenly dies on me near Watertown, NY. I could actually drive it as the engine started again but kept dying on me due to lack of power. Long story short, I had the CEL checked out and it turns out 2 new codes were added to the normal P0400. P0100 and P0101. They indicated the mass air flow sensor problem. Replaced it and now the engine runs better than it has in the last 2 years and the CEL hasn't come back on yet. So, if you have this problem, it could be the MAF. Outback 1996, 2.5 liter engine.
Tabipapa