Just logged in to post my outcome and am happy to report that cleaning the MAF fixed the issue. No codes or SES light. Thanks for all the help from the forum.

 

SO driving to work and SES pops back on, plus showing the same code.. although the Ultra Gauge is showing that the fuel trim is fine as the little circle in the top right hand corner is no longer ope, but running on closed loop? Could it be something needs time to reset internally?

 

Many codes associated with fuel and O2 sensors require two drive cycles (crank up from cold engine start) to pop up. Should not need internal reset, but may need a few more cycles to learn your driving habits with cleamn MAF.

 

Ready to push her off a cliff, if only she wasn't so pretty. Cleaned Maf, All 4 O2 new, checked fuses, cannot find exhaust leak, Plugs and Wires are year old and look clean now (8MM STI), Cannot find VAC leak, Cats replace by land Rover 1 month before I purchased it.... still getting 0171 & P1171.. What Next?

 

Make sure all vacuum plugs are snug, if any are loose replace. Hows your air filter look? Maybe check intake tube for leaks. Also clear and drove some more just to make sure theres still an issue.

 

Kept driving and codes still present and had a brief moment of flashing SES, so I ordered a new MAF, as it's the only part that I haven't replaced, and now I'll wait to see the outcome once the new MAF is installed

 

New Maf arrived and installed, although took 8 days to get here after date of purchase, but trucks is running smooth as glass (I hope it sticks)

Thanks for all the help

 

New Maf arrived and installed, although took 8 days to get here after date of purchase, but trucks is running smooth as glass (I hope it sticks)

Thanks for all the help