Help we replaced steering col. on 1999 tahoe an know it is flashing sec. an will crank an turn right back off stuck in garage is any code or something any one could help me with

When you say it starts up and dies right after, how long does it run? A faulty Passkey code to the security system will allow the truck to start and then run very briefly for about .5-1.5 seconds then die. You can try resetting the Passkey system in the bcm and see if it helps.
Put the key in the ign and turn it all the way forward to the IGNITION position without starting the truck. Now leave to key in this position for at least 12 mins. After 12 mins or so, turn the key back to the OFF/LOCK position then forward again to start the truck.
If it is a security problem, this should take care of it. Some suggest to do this 3 times, but it worked for me the first time.......... dmh

I had similar starting problems with my 99 Tahoe. It turned out to be the anti-theft device was malfunctioning and not recognizing the key so it would turn off the fuel pump and eventually the fuel pump went out too. Since having this replaced ($555.00 with parts and labor at the dealership) I have had no more problems at all with my truck and have actually braved taking it on a 6 hour road trip and had no problems with it leaving me stranded. Since that road trip, I have gone on several more and have full confidence that I will no longer have this be an issue.