my 93 850 recently has been actin a little funky. When the car is running and in park or just stopped and I turn the wheel the rpm's go down a lot like its losing power. Also if i turn on my lights and fog lights it seems like it does the same thing, but it never stalls but its been down to as low as like 450 rpm's.

Anyone have any idea? I was thinking maybe it was a vacume leak, or a power steering problem but my knowledge is limited since this is my first volvo.

You may want to check the serp belt and the tensioner. Sounds like it may be slipping

Or the Positive Terminal end is bad.
Not allowing the car to charge properly.

well I dont get to get online much but when I have a question you people are always helpful. Thanks .