Haha - I'm an expert at this.
The reason it flashes theft is you're using a remade key that does NOT have a chip, it turns over for like a second or two then just dies, right?
Yeah, happened to me, then I decided to try the other key (which I didnt know had a chip) and it worked fine.
Good luck with a new key, bub, I just had one made. $130; they had to hook up to detroit and everything to get the codes. If you have two, though, you can make a 3rd for 30 bucks or so (whatever it costs for an unprogrammed, chipped key).
For anyone who wants to know how to make a third with two PROGRAMMED keys, heres how to do it:
1. Buy a 3rd unprogrammed key
2. Take key one, put it in the ignition and turn it forward so the electronics are on (dont start the car)
3. Wait about 5 seconds, then shut it off and remove it
4. Take key two and repeat the process.
5. Then take the third, unprogrammed key, and do the same. The car recognizes that you have two different programmed keys and programs the third for you.
Pretty neat, eh?