Hey folks. I have a 1989 Cabriolet that, overall, is a great little car. But lately when I drive it, when I come to a stop the RPM's go way low (~200-300), and fluctuate between there and around 1000. This fluctuation is pretty rough for maybe 30 seconds or so, then it smoothes out and settles around 700. And yesterday it got even worse -- I drove home from work and stopped at the grocery store. From when I pulled into the parking lot at the store, and then when I left the store on the way home, every time I came to a stop the car stalled. It always started right back up no problem, and idled smoothly at ~700 RPM's. But next time I came to a stop, it stalled again.
Any idea what might be the problem? I saw something like this earlier this year, but it wasn't as severe (the idle wasn't as rough; it would just dip once upon slowing down/stopping). I had the valve cover gasket replaced, which fixed the issue. But the problem is back, and worse than before. Any help you can give as to what I can look at would be appreciated. I'm not much of a mechanic, but am willing to do basic stuff on my own.
Thanks!
Corey