Help 98 truck

I have a 98 V8 454 Chevy truck and the check engine light is on. I got a code reader. It shows a code PO171, system too lean , bank 1. Does anyone I any ideas what it could be?
Thank you for your help, Robin
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Low fuel pressure ,any entering the engine unmetered, a cylinder misfire, a malfunctioning maf if so equipped, a full scan will look at baro readings, fuel trims, and sensor inputs, a vacuum leak can also cause this.

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