1999 Legacy 2.2 (phase 2 NA). Noticing that my throttle plate angle is at 1.2-2.0% vs. 0% at idle. How do I go about adjusting this back to 0%? My TPS voltage is at 0.48. Thanks! 
 

-Will

I'd first remove the intake tube and clean the throttle plate and intake.  There is a adjustmet screw on the drivers side of the linkage.  Make sure the cable has some free play.

I'd recheck then.

If you’re messing with the throttle body idle position, read up on the requirements of the TPS adjustments (if needed). 

On the earlier models, any adjustments of the throttle butterfly required an adjustment to the TPS so the ECU was still getting the correct readings from the sensor. 

Does the FSM say that you need 0% throttle at idle? I’d check into that first before adjusting anything. 

Are you experiencing any issues or have you just looked into the data/sensor readings and thought “that’s not right”? The engine still needs air at idle! 

Cheers 

Bennie

i would not touch any adjustments until after making sure the plate and throat are spotlessly clean.  there could be dirt/carbon/etc build up that is not allowing the plate to close properly

make sure everything is clean, then recheck function... then, and only then do you touch adjustments, if needed

Throttle body and IAC valve are both clean. Having issues with a hanging idle where idle wants to hold at 1600 rpms after warm and first acceleration. If I restart idle will be at ~750 rpms until first press of accelerator. Vehicle has been smoke tested.

Check that the throttle pedal retracts itself fully when at idle. It is possible that something can physically interact with the pedal, stopping the pedal-spring from doing its job OK. Or the spring itself might be 'tired'.

Edited April 17, 20223 yr by forester2002s

also check the throttle cable.. there should be just a small amount of play in the cable, at the throttle body, when idling

make sure it is not kinked, or pinched anywhere along its path.

I wonder if the issue lies with your IACV. My sister’s EJ251 has an issue with the IACV where it will stall sometimes when coming up to a stop or when changing down gears into a slow intersection turn. From time to time the check engine light comes on and the code is always for the IACV. 

Sounds like your issue could be along the same lines, particularly if your IACV is the plunger style unit with the rubber dome shaped seal on the end. Seems that these seals wear or crack at the contact point and leak air, resulting in the idle issues and resulting check engine light. 

Cheers 

Bennie