Vince,
We could only guess and although inconvenient, using the warranty as you are is probably the best course.
It might turn out to be something simple, but conversely it might be simple and seemingly unrelated. So diagnosis can be really tricky.
At best all you will get online is possible guesses, and even then can very on little details not included like what engine etc.
My best guesses would be:
1. Faulty ecu is definate posibility.
2. If the clock spring was previously changed then a damaged ignition switch is a definite posibility too.
3. Faulty alternator - more common on older cars.
4. Incorrect spark plugs. But i think unlikely in your case.
Good luck & keep us posted.

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