Hello,
I have a 99 S70. The rpm's drop to around 500 and then jumps back up to 800 when I slow to stop. I have also noticed a flutter on the rpm's with the a/c on at idle. The flutter disappears when I turn the a/c off. I don't know where to start in diagnosing the problems. Any input would help.
Thanks, Bob

 

I had the same problem. It turned out to be a vacuum leak. Maybe try that? I still have the problem but it isn't nearly as bad. The car used to stall when i let off the gas too quickly

 

Thanks, I'll try looking for a leak. I have been told the IAC may be dirty. Any input on that?
Bob

 

Yes, dirty IAC would be my first guess. Try cleaning it out with carb cleaner.

Also ck for any codes being set; is your ck engine lite on?

 

No codes and no CEL.
As for cleaning the IAC. I looked at mine and couldn't figure out how to get it out of the large hose leading from the MAF to the TB. Does it just slide out or do I unscrew it? I see two screws on the side but they appear to be neither torx or hex.
Thanks, Bob

 

I have found that my 99 S70 doesn't have an IAC but does have an AACV. Does anyone have any experience with these. Can they be cleaned? Could this be the of my rpm flutter?
Thanks, Bob

 

I was able to remove the AACV and give it a good cleaning. This took care of the problem. Thanks for your help.
Bob