Help w/ Honda CRV 2007 butterfly valve or throttle body itself

Portland OR

Description

Dude helped replace my starter and "cleaned everything" as he went. Now it's idling weird, accelerating weird, etc. Check engine light is on: code was for the throttle body. Seems like the butterfly valve isn't closing entirely and is messing with air intake? Maybe needs cleaned better. Maybe throttle body needs replaced. Let me know how you'd diagnose/fix and what your fee is. Thanks!