I have a 2008 LR2, 48,000 miles. It sputtered and stalled several times recently, then cleared up and ran fine. An OBDll code reader said bank1 is lean. I suspected that there might be a vacuum line leaking (sucking air) causing the lean reading. On the passenger side of the engine (left as you look into the engine compartment) there is a purge line that goes to the canister. Everything is so tight in the engine compartment that I can't see any lines. When I give the idling engine a brief tap of throttle to raise RPM several hundred and off, there is a strong sucking hiss. This does not continue, but you only hear it the moment the throttle is opened. Is this a normal intake sound, or a sign of a possible vacuum leak? Thanks

 

you have to test the system for leaks to determine if its a problem.

 

My 2008 LR2 had DTC P0174 - System Too Lean (Bank 2) which caused the Check Engine light to come on.

Researching common causes, the first problem suggested was a vacuum leak. If you can hear a hissing sound while the engine is running, then you've found a rather significant leak. But a very small leak won't be found by human hearing. You'll need to take it into the shop and have them perform a smoke test.

However, the next most common cause is a dirty Mass Air Flow (MAF) Sensor, which is attached to the engine side of the air cleaner housing. I removed mine and it did not appear dirty to my eyes, but the delicate filaments in these sensors are very sensitive and can be impacted by microscopic dirt or pollen particles. I cleaned it using MAF Cleaner Spray I purchased at my local auto parts store. Since cleaning it, I cleared the code and it has not come back on, so this was likely the problem.

A few more notes about the MAF: It is a very fragile and expensive component so you have to be careful while handling it. Youtube has a couple videos showing how they are removed and cleaned on other vehicles. In my case, I could not easily remove the wiring plug from the MAF and I did not want to risk breaking anything. So I just left it plugged in while cleaning it over the engine after laying down a large plastic garbage bag below it to cover everything else. Also, you MUST use special electronics parts spray to clean it. The cheapest is sold as MAF Cleaner Spray in most auto parts stores. Finally, my LR dealer told me that LR does not clean this item as one of its routine services. Their policy is to replace it, not clean it, which seems odd to me because it is generally recommended to be cleaned on other vehicles every time the air filter is changed, about every 30K miles. The part alone costs over $150, so I would try cleaning it before replacing it.

 

Thanks LR2 Driver. I will get some cleaner and clean the Mass Airflow Sensor. Seems like a good possibility for my problem.

Alfadavid

 

The MAF is located as shown by the red arrow in the attached photo. You just remove two screws. As I indicated in my previous post, I could not easily pull off the wiring harness so I sprayed it while still attached. You need to spray inside where the two small filaments are. Don't touch them with anything but the spray.

Let us know how it goes.

 

OK, so my problem isn't the MAF. I was hoping it was that simple. I cleaned mine first. no change. I bought a new one, installed it, manually cleared the code and my check engine light came back on, with the same P0171 code.
If i have a vacuum leak, what is the fix and how much should I expect to pay for fixing this.
note: my vehicle is an 06 LR3 and has just eclipsed 100k miles.

Thanks for your help and any suggestions. If I don't get this taken care of in the next week, I will have to park it, as I can't pass smog with a check engine light on and my registration will expire at the end of the month. It's super annoying to me, since my LR3 is running beautifully and I love to drive it. It's a great car.

Thanks