My 00 Outback started intermittently running very rough, very sluggish acceleration and threw a P0170 code (Fuel Trim Malfunction)
Did some research and got a ton of possibilities.
I dropped exhaust and replaced front O2 sensor, re-installed exhaust with new exhaust gaskets and replaced air filter while I was at it.
Car in A-OK now. In all approx 2hrs.
Edited by soobyhobby, 05 April 2014 - 01:08 AM.