P0171 lean code?

So it starts up, dies but then restarts and dies again? How long does it run before it shuts down? A few seconds or longer? The description sounds like the fuel pump isn't turning on after the initial prime cycle. That would cause the stalling and the code as the low pressure fuel would not be what the PCM expected and it would run lean as it runs out of fuel. The PCM triggers the pump relay on for the initial prime, then once it sees oil pressure and a voltage rise from the alternator it turns the relay on to keep the engine running. The other option is a week fuel pump. Both could cause this problem. So try this, turn the key on then off, repeat this a couple times over a minute, now start it, does it run longer or the same amount of time as just starting it? Did this happen suddenly or has it just gotten worse? Do you have access to a dealer level scan tool that can control the fuel pump?

I agree with STEVE W. we need more information to help you, please go over his guide to get started. It could be a dirty MAP/MAF sensor.

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

Please go over this guide and get back to us.