I'm getting a P0171 code on my 2003 Dodge Ram 1500 5.9, how do I fix it?

Hello, you'll have to perform continued testing to find out the source of the lean running code. If you do not have also a P0174, then you should focus on the 'bank one' system itself and only that. If you also have a P0174 code, it indicates both banks have a lean running problem, which would point more to an air intake issue. All of it is guessing until hands on inspection is performed. Seek a local shop near you to test fully and offer a diagnosis. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops