My Volvo V70 XC 2001 has been having random idle issues. Dying, sputtering, erratic idle, and a very rich exhaust. No check engine light initially. I changed spark plugs, cleaned MAF sensor, and put some ISO-HEET in my gas. I thought the HEET fixed my problem.

When driving to work today at highway ...

Please read my Reddit post and help me out! It is not letting me copy text from my post, so here is link.