Engine Performance problem
2000 Buick Lesabre 6 cyl Front Wheel Drive Automatic 130000 miles
My Lesabe started running poor and got a P0300 code. Changed the plugs and wires, no better. Checked for spark at the coils by pulling the wires off while motor was running. Found the first had no spark and the other two did. So I swapped the first and second coils and found that now the one that tested good had no spark and the other no had spark. So its only the top coil that wont fire. Ignition module?