Subaru Repair: Rough idle and poor acceleration in Legacy, legacy wagon, autozone

Question
I have a 1992 Legacy Wagon 2WD, automatic, 2.2L 4-cyl, no turbo, with about 185K miles. The engine was running fine until a few weeks ago. Now it idles very rough, and it almost dies when the car is at a stop. At idle, the rpm's cycle between a normal level (800 or so?) for maybe a second and then drop real low and almost stalls for a second, and keeps cycling like this every second or so. The check engine light is on steady now whenever I drive it. Also, the engine accelerates poorly -- even when I stomp on the accelerator and it downshifts and the rpm's go up, the car is very sluggish compared to just a few weeks ago. What do you think could be wrong? I would like to fix it myself if possible.

Answer
Hello Steve,

     First thing to do is take the car to someplace where they can scan it. I here autozone does it for free. Your answer may be there. Whatever is causing your engine to do this may be the reason your check enigine light is on. I hope this helps.  

                             Thanks.
                                Frank