I have a 2003 Ford Explorer that hasn't been idling well lately. It normally idles around 800 or 900 rpms, but lately it will slow down to 400 or 500, then burst up to 1100 and repeat the process again. It doesn't do this all the time, maybe only half-time. Occasionally the rpms get so low that the engine dies, but that only seems to happen when I'm turning AND braking at the same time.
I don't have any idea what's causing it, and I really haven't even pinned down a common variable for when it happens. It seems to have started with the cold weather, but even then I couldn't tell you for sure.
Does anyone have any ideas or suggestions before I take it in to the shop?