Recently acquired (two weeks ago) an 05 LR3 with 74k miles on it. I was doing some routine maintenance and after changing the air filter (which was full of leaf particles) I got this code. Lean code 0171. Car runs and idles fine. I rechecked the seating of the filter and see no cracks in the filter box or tubing. I cleared the code and it’s back on 30 miles later. I have tried some seafoam as well. I just replaced the MAF sensor and cleared the code and it came back on within 20 miles.

I do have a PCV valve and some fuel injector cleaner that I will try next. Anything else moderately easy to try before I take it to the Indy shop? (Fuel pumps/injectors are beyond my skill/time available). Thanks

 

Lean codes on these are typically from unmetered air leaks - not always but usually (there are soooo many lean code threads in the forum archive). You probably disturbed the air inlet tubes enough to allow a crack or dry seal to let air through downstream of the mass air flow sensor.
Just fyi, if you're going to throw a MAF part at it, only use a Denso or oem Land Rover one - anything else is known to be trouble with these.

 

Well, I replaced the PCV valve and drove about a 100 miles today and it appears to be fixed. I did pay particular attention to the resonator clamping. It now has noticeably more power at low RPMs and idles a bit quieter.

The MAF sensor I have is a Delphi from Atlantic British. I kept the old one and will clean it since it likely wasn’t the problem. I also still have seafoam working through the tank, which may have helped.

 

Clogged injectors can also cause lean codes - fingers crossed that was it and they're cleared up now. You might want to also do a can of BG44k in the tank before your next oil change. It's strong stuff, so the recommendation is to change your oil after running that through - I suppose because it can loosen up and deposit some carbon in your oil....

 

By the way, there are a number of reports that the Delphi MAF often doesn't work right in these (just saw another such report on a Facebook LR group today) - so if it turns out you do actually need a MAF, Denso is still the only bulletproof choice.

 

The one I took out and still have is the OEM Denso, which I will clean and keep just in case. But since the light is off now and it’s running a bit better, I’m going to leave well enough alone for now.

 

Now this is funny. I put in a bottle of BG 44k and about 2/3 of a tank of gas into it, light came on it’s now reading P0172 and P0175, too rich in bank 1 and bank 2. Probably going to fill it up and reset and let the computer adapt over time.

 

They are a source of constant amusement if you have the right state of mind
I'd just let it run through the 2/3rd tank personally and see where you are when that is used up.

 

I did buy this as a project car. I might have an excuse to clean the throttle body now.

 

So, for posterity, the check engine light went off and the codes cleared after about a half tank after the next fill up. Changed the oil and it was very black. That BG 44k must be strong. I am definitely getting a smoother idle and more low end power. I also am getting about 2mpg better in mixed driving.