Code P0171

No problem with truck since iv Owened over a year (bought in 2013)
Today check engine light came on, code P0171 by it self popped up. Truck hasn't given me any noticeable issue( no sputter or stall or anything) just sucks down a lot of gas but the distance I drive to work it's hard to tell if it's sucking down more than normal.

2003 f150 4 door 5.4 fX4

What does the code really mean and where should I start about fixing it. Thanks

 

Have you ever scrolled past a sticky titled"P codes diagnostics and probably causes". Lots of helpful info there that a fellow member, ibd2328 took the time write out. CHECK IT OUT

 

System to lean. Have you started with the basics. Clean MAF, foam intake, clean throttle body?

 

Starting with the basics is a good! Dollars to donuts says those suggestions do not fix the issue, however they are good maintenance items. If those were the issue, he would have the codes for both banks, eh?

OP, you're going to want to look for a vacuum leak, intake gasket leak, or exhaust leak...on bank one.

 

I'm just saying if you haven't done it, it's a place to start. Wouldn't cost much, and it maybe needed. Then can go from there. Get a can of carb cleaner and spray lines and around the plenum. Make sure nothing has pin hole leak it, or warped.

 

P0171 and P0174 are a pain to figure out sometimes.

I have both 171 and 174 (I clear them and they sometimes instantly come back, sometimes a few days). I need to check all my vacuum lines.