Really need some help. Intermittent problem with electronic throttle not responding. Often I stop at a red light, etc. & then when I step on accelerator the engine doesn't rev normally. It has loping idle between 800 & 1000 rpm. When I step on gas pedal engine slowly revs up to around 1500 rpm. Check engine light comes on & cruise control light flashes. I have pulled two error codes: P2109 "Throttle /Pedal Position Sensor A Minimum Stop Performance" & P0638 "Throttle Actuator Control Range / Performance (Bank 1).
After I shut off the engine & turn it back on a few times, it revs normally. Then it often drives fine for a day or two. I don't own a WRX (I wish I did!) but I believe my '05 Subaru Forester 2.5X (normally aspirated,no mods) has the same "throttle-by-wire" system as the WRX& you guys are often very help on tech stuff.
Any recomendations on where to start? Throttle position sensor & throttle body appear to be one unit & sell new for $570ish. I was planning to take it off intake manifold & clean everything (I have new gasket). Mabe try to clean sensors on throttle & pedal with electric contact cleaner spray?
Any help is really appreciated!