New 2006 LR3 Owner, Purchased car at an auction, with CEL on so I don't have any background on it. It's a 4.4L SE V8 with 110K miles.

The car runs and idles great, no issues at all other than the CEL.
The LTFTs are around -20%; STFTs hover around zero indicating a rich condition
Attached is a picture of some data I pulled from the OBD. A friend suggested I pull the MAF sensor and take a look at the data, so that is attached as well.
30 seconds into pulling the MAF the system went into CL-Fault, but the STFTs were starting to correct the LTFTs, indicating the problem is fixed, but I'm not too sure if in CL-Fault its just running off an O2 table or something.

Things I've checked already:
Fuel Pressure at 65psi
I've canister cleaned the injectors
Replaced EGR valve
Cleaned the throttle body
I've ordered a new MAF - But I don't think it's going to fix my problem.

Next items on the to do list:
Have the ECU re-flashed
Any other things I'm missing for both banks to be rich?
Any vacuum leaks would normally cause a lean condition.


Thanks for any help you may offer.

 

Don't be so sure about the MAF not fixing your problem....usually throttle body and/or MAF are the culprits.

 

In my experience the MAF is not typically the culprit when the LTFT is rich, because that means that MAF has to overreport the air coming into the intake.

When the hot wire is dirty it can't read all the air coming in resulting in lean long term. Long term rich most likely is stuck fuel injector or faulty fuel pressure sensor (just had this in wife's volvo).

OP.. did you measure fuel pressure with OBD2 scanner, or with a mechanical gauge?

 

I measured 65 psi with a mechanical gauge.
I'm assuming a stuck injector would cause the engine to run poor?
Are the O2 sensors pre and post catalytic converter? Is the primary one located on one side of the engine to help diagnose the injector bank?
I'll let you know when I change the MAF if it gets better..

 

I replaced the MAF and the problem is fixed! The old MAF was over reporting! I would have never guessed this. The original MAF was a remanufactured one, replaced with new. I've attached the good readings from the MAF at idle and other sensors.

 

Awesome news! So you just swapped sensors and thats it? No code reset or battery cables removed?

 

Bwahahahahaha!!!! Houm wins!

 

As soon as I installed it, I pulled up my live data on a code reader and saw the STFTs go in the +20% range, compensating for the LTFTs in the -20% range, so I knew it was fixed. I did reset the codes, but the CEL light came back as soon as I drove the car. The LTFTs are stored in memory cells based on RPM and load. As soon as I entered another cell the stored LTFTs were loaded and the CEL light turned on. After driving it for 2 days the CEL light went off on its own. I believe I could have wiped out the LTFTs by resetting the battery, but I wanted to make sure it was fixed, and not just cleared...

 

 

I'm getting this same issue right now...going to try swapping the MAF and hopefully mine will be as easy as yours...thanks for the post...