I have a 2004 Impala which has about 55,000 miles on it which I have owned since new. About 6 months ago it all of a sudden began not starting, and since then it wont start approx. 5 or 6 times a week, sometimes it will go 3 days with no problem, then it won't start several times in one day. When it won't start , you have to let it sit for about 10. When it won't start the secuity light will come on in the message center. The key for this car is in the dash. I've heard this is a problem with several GM vehicles around this same year, and there is no specific fix for it. Any input for a solution would be great.