Hi Sheit:
My CEL only comes with AC on. If I don't use AC,
it's okie dokie. I do experience some surging at idle some times (from 900 to 1100 rpm), which I don't think is a big deal (usually those come from vacuum leaks but it could be a lot of things).
If I were you,
I would reset the CPU to clear the code. You can just pull fuse 11 (I think that's the 1) for a few seconds and put it back. Drive without AC on for a few days (if you can manage of course). If no CEL, then start using AC. If CEL comes in, then we probably have same pb.
If CEL came back without AC on, I think others have experienced this so you can search forum for 'CEL 0171' and you shall find lots of info. Actually, a previous post on this very thread had the list of things to check with this code.
Hope this helps,
Hugues -