Security light flashing

Well after having my car at the local garage and alot of money later I still seem to have trouble with my car. At first it would run good for days then it would just turn over and not start. They replaced a module under the distributor and it worked fine for two days. Next they changed the fuel pump and it worked for a week. Now the security light flashes when you turn the key on and it runs for about 3 seconds and shuts off by itself. I was told I need a new key, new ignition switch, some type of plug in the steering column, crank sensor, the list goes on. When it was scanned a p1629 code came up? Anti-theft code I think? Any suggestions please. Tired of dishing out money with no solutions