Started in ony day and it would barely run. Checked for spark and only had fire in 2 and 3. Noticed plug wires being bad almost broken so replaced and still nothing. 1&4 cylinders run off same coil pack so I figured that would be the problem. Just put on a new coil pack and it still isn't firing on those cylinders. Has anyone had a similiar problem or know what the problem could be. I thought if it was the ignition module or crankshaft position sensor then no cylinders would fire?