Engine Performance problem
1997 Ford Station Wagon 6 cyl Front Wheel Drive Automatic 155660 miles

My car started about two days ago emitting exhaust on the inside of my car when I turn on my heat. My check engine light has been blinking on and off for the last week only when I sit at a stop light too long and the car shakes when sitting in park and is worse when you brake and sit at a light or some other stop. My car is a 1997 Ford Taurus Wagon LX 3.0L V6 24 valve engine. I went to Advanced Auto Parts and they did a diagnostic, three issues came up. First the EGR had insufficent flow, then piston #5 was not firing, and lastly bank 2 was "too lean". The gentleman told me that to stop the shaking changing the EGR valve would help. My father did so this evening, but the same problems still exist. What other problem(s) could this be? Thanks for your help.