My CEL started flashing again tonight. I have a OBD II scanner which showed misfires in five out of the six cylinders. I replaced the crankshaft sensor and drove it for about 15 minutes. The CEL started flashing again. Read the codes which showed misfires in cylinders two, four, and six. I am going to change out all six plugs, coils, and seals. Also will need to replace the intake gaskets as the upper intake will need to be removed. Any other advice would be appreciated. It's a 2006 CTS 3.6l with 116000 miles on it. I bought it last year. I had to have a new radiator put in because my transmissions lines rusted out. Also, ever since that was done when I start the car up and drive it, there's some sort of a rattle or something when I step on the gas.