I have a 2002 ford f150 5.4 that is sputtering hesitating, and popping. The code is P0171?

I have a 2002 ford f150 5.4 that is sputtering hesitating, and popping. The code is P0171?

How many miles? The 'little' coils mounted on top of the spark plugs start dying at around 100,000 miles.

P0171 is System too lean, bank 1. You are looking for an intake vacuum leak on bank 1. If that is where the PCV valve is attached, check the PCV hose. Ford had a lot of problems with the hose ends tearing.

Sputtering, hesitating, and popping sounds like inadequate fuel going through the fuel line going into the engine. It sounds like a small pinhole leak in a fuel line. Second guess would be a leak in the gasket seal around the engine, allowing air into the engine somehow. Sputtering is caused by air bubbles and too much air getting into the engine, and hesitating means that fuel is not being continuously fed into the engine at a continuous, even flow, but something is interrupting the fuel flow. Check the fuel line for minor pinholes or cracks, then check the engine for loss in pressure due to a leak in the gasket seals and seals around the incoming fuel line into the engine as well as the seals around the fuel injectors.

The P0171 code means that, on the first bank of the engine, the fuel system is running weak or a vacuum leak exists near this side of the engine.

If you stand in front of the vehicle on the grill there's an oval shaped silver and blue logo with an F word in the middle of it. That's your problem right there.
(Formidable On Road Disaster)
(For Only Retarded Drivers)
(Foreign Organized Rebuilt Deathtrap)
(Fell Over, Reportedly Dead)
(Fairly Offensive Ridiculous Designs)
… I can do this all day.

P0171

How to fix?

Google rawks!

Most likely a vacuum leak. I have seen this code on two different vehicles. On the first vehicle, I mistakenly pulled a vacuum hose off of the engine while doing maintenance. On the second vehicle, a hole was created in a hard plastic vacuum line by rubbing against another metal part.