I have a 2001 pontiac bonneville with a fuel injected v6 I was driving it about a month ago when I lost power and the motor started to shake with the check engine light flashing, noticed that cylinders 3 and 6 were not firing so I replaced the coil and ignition control module because both were bad and yet the check engine light still flashes with a shudder and smells like gas, what could it be?