Just bought a 2002 outback wagon with the 2.5 5 speed. It has a galloping idle and sometimes under load it has no power. Its at my uncles shop now and we can't figure out whats going on at all. We have swapped complete throttle bodies out of a 2000 2.5 with all the speed motors and idle air control valves and we did the MAP/tempature sensor. We put all the parts from the 2002 on the 2000 and the 2000 ran excellent while the 2002 still has a serious idle problem. We even swapped coils, wires and checked the plugs. HELP!

Here is some interesting reading ... about reply #31, I posted a fix that I have now 'tripped' over a few more times on others cars I fix.

 

http://www.subaruforester.org/vbulletin/f88/low-idle-stuttering-erratic-jerking-various-rpms-76450/