I have a 97 Impreza outback sport, 2.2l 5mt. I keep getting a 1507 code and the odd time a knock bank 1 0325 code. They will always clear and I now get the 1507 every time I drive the car, it goes into safe mode and runs like crap often but not every time. It does not seem to matter how the car is driven, as in speeds or distance, it always comes on at some point. I have searched this topic here and read I think all the threads on the subject that I found might relate to my situation.
I have cleaned the idle air control valve, it is clean as a whistle and moves freely. I have checked vacuum lines and replaced a few. I've disconnected the neutral switch as was suggested in a few threads, though I would love to know how this is related?
Still have the problem, is there anything else I might try before sourcing a new idle air valve? Would it be worthwhile to try a used one?