If it were me I’d be getting real tired of trying to find the problem and probably try the IDM next. I hate to throw parts at something without proof of exactly what’s wrong but that would be my next step. I have seen then on car-parts.com and eBay pretty cheap (like around $100). I’m not sure if any site vendors sell them or not. Maybe one of them will chime in.
And I haven’t helped you fix anything yet, if we do figure it out I’ll skip lunch and you can pass it on by helping someone else. I’m about out of ideas, maybe someone else will have a fresh idea and post it.