97 gt starts then dies thieft light flashing

Hi just joined forum . I have a 97 gt the problem is when you insert the key in the ignition ant turn to on the thieft light flashes rapidly and when you crank it it will start but then die . If you just turn the key back to on without turning it all the way off and try to start again it cranks but won't start at all. If you turn the key all the way off and then try to start it it will start and then die and the thieft light is flashing rapidly. It has done this 3-4 times in the last few months but then I'll try it and it starts and runs normally. I'm afraid to take it anywhere for fear that it won't restart . I've changed the battery in the key fob I've tried disconnecting the battery tried cycling the key on and off and nothing works so I'll leave it alone for days or weeks and all of a sudden lit will start and run normally for days or weeks but then it starts doing this. Any help appreciated.....Smitty

Thank you for your response. I will try that and post the results. My initial thought was when I turned it all the way off it was resetting something in a module

I've read some other postings of with similar issues and a common question is when you turn the key to on dose the theift light go off after a 3second prove out, it dose not. I forgot to add this to my initial post. Again thanks for the help.

Just installed new ignition switch. Car started right up no prob . Thank you so much to WMBURNS YOU ROCK.

Smittyo said:

Just installed new ignition switch. Car started right up no prob . Thank you so much to WMBURNS YOU ROCK.

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Well the saga continues . Today went to start it up and go for a cruise , same prob. so I removed the ignition switch and reinstalled it and again it fired right up. So at least I have an idea where to look now. I'm waiting to see if it happens again I'm going to try wiggling the plug/harness on the ignition switch and see if I can get the it to start. Will post results

As a side note I was curious about the old ign. switch so I drilled out the rivets to see what was inside rows of contact's that slide back and forth when you turn the key but didn't see anything really wrong except normal wear.