Land Rover Repair: 01 Disco II, air fuel mixture, engine management system

Question
John-

I have a 01 Discovery II W/ 48,000 miles.
I have fault codes P0171 & P0174 present (engine banks running lean/ O2 sensors).  My Service engine light comes on when I drive the car longer distances (20+ miles) and gets to a certain temperature.  When I only drive shorter distances (to and from work, 6 miles a day) it resets itself and doesn't come on.  Its done this consistently five times now.  Any insight you can give is much appreciated and what tips do you have for trying to solve the problem myself before handing it over to the LR dealer?
Could the enginge running lean be a serious problem?

Thanks and I appreciate your input.

Nathan Thompson

Answer
Hi Nathan,

what you have is a weak air/fuel mixture that has less fuel to air ratio.  

It could be injectors, it could also be MAF sensor problem.   Clearly, you'll need specialized diagnostic tools to determine where the problem lies.  IF it was just one sensor involved, it would be easier but its not the case.  The more complex the Bosch engine management system, the more reliance you must have on diagnostic devices.

So take your Disco to a LR dealer or a trusted LR experienced technician.

Best of luck,

JohnMc