ADDITIVE ADAPTIVE MIXTURE CORRECTION, BOTH BANKS!!!

Help I have codes p1171 and p1174 the description is " additive adaptive mixture correction"
on both banks. Its a 4.6 v8 with secondary air system. I changed the MAF sensor yesterday and cleared the codes but it back after my drive to work today :-(

Seems to be running a little lumpy too at low revs. I put some seafoam fuel treatment in a few weeks ago and wonder if it has set something off.

Any information i can get will be appreciated. I've been trying to get to the bottom of it for weeks an cant seem to get any information on the issue other than MAF.

P1171 and P1174 relate to Mixture too lean in bank one and Mixture too lean in bank two respectively. I would think you possibly have a moderate vac leak post MAF - if no other codes are present. Or possibly but unlikely a fueling issue affecting both banks, on the basis the MAF replacement you bought is a genuine functional part , not a pattern part as those often cause issues on all breeds of engines.

If you have the capacity to see live data with your OBD scanner, that will help you along without the need for more shotgun repairs (such as seeing if the new MAF is providing data within the expected range)

Many other posts on the forum with similar issues if you hunt about, good inspiration to be found. E.g - https://www.landyzone.co.uk/land-rover/system-too-lean-bank-1-and-2-4-6-v8.155639/

Thanks for the help Mr Goc3k.

When I got home from work today I took off the air intake box and sealed the intake after the MAF sensor. I blew in air from my compressor (at low pressure) and sprayed a bit of washing up liquid and water around the hoses and joints of the intake and secondary air system..... Nothing!

I could just hear a slight hiss coming from where the injectors are sat right under all the gubbins on top of the engine. I managed to direct a bit of spray in that direction and sure enough. I got bubbles from the first slightly visible injector.

So... Im thinking it will need new injector seals? is this a big job? and time wise how long should i be looking at? (I'm not bad on the old spanners)

I just cant be arsed!

Any input would be appreciated. Thanks

It would smell strongly of petrol if the injectors were leaking, was the injector body itself actually causing the bubbles or just that region? Changing the seals is not too involved, generally.

I'd be inclined to check the fuel pressure regulator to see if that is the source of the sound/leak as that would effect air fuel ratio if faulty

Yeah it was the little O-ring around the injector itself that was bubbling away. I Just got a new set off flea-bay around 20 bucks. Ill be doing them next weekend along with new plenum gasket, plugs and wires. If that doesn't fix it ill go back to scratchin me head.

Aye a reasonable leak might drop the rail pressure enough at high RPM to cause a lean running scenario