I have a 2001 Legacy sedan, base model, 5-speed, only 80,000 miles. Recently, the idle has been erratic. Sometimes it dips down below 500 rpm and the car will stall out. Then it will jump back up to standard idle, ~750-800 rpm.
The engine check light is NOT on and I can't find any codes with my code reader.
I have solved the stalling problem temporarily by raising the idle with the accelerator cable adjustment. Inelegant, but it works.
What are some likely culprits? Is there an idle enrichment solenoid? Mass air flow sensor? Another sensor or elecctronic doodad? By the way, before this problem came up, I noticed that when the engine is cold, the idle would often go WAY UP to 2500 rpm plus for the first three minutes running until the engine started to warm. Maybe related?
THANKS IN ADVANCE FOR ANY SUGGESTIONS!
Jeff in frigid cold Boston