Having some problems with my 1991 Legacy. Has a 2.2L engine. At anything below 3000 revs, the engine runs extremely rough. Barely is able to idle, when idling, the whole car shakes and engine seems to want to turn off. Tach show just below 500 for idling, seems kinda low. Also, at below 3000 revs, there is no power, I have to floor it to get anywhere. Above 3000, car runs ok. Added some fuel system cleaner to gas tank not to long ago, hasn't really helped. After a short 5 or so mile drive, there is a very little bit of smoke coming from the left bank of cylinders. Don't know what's wrong. Could it be timing or spark plug wires??? Thanks for your help in advance.