Hi everybody, I have a 2003 Impala LS with a 3.8L engine and I have some problems with my transmission. The problem is when I go 100 km/h and more, the transmission don't change gear and the check engine light start flashing. I go at Canadian Tire, because GM was close and the technician told me that there is no alarm on the computer. Everything is working good on the motor. But they can't told me what wrong. Thanks very much to all will give me a response.