P38A MAF etc opinions

There are a few adaptive things on the 38 never counted them myself just reset them and boom, done..

No harm in resetting them TBF..

As for being done after major work, nope.

The simple act of flattening or disconnecting the battery will erase the adaptive values and they'll have to be re-learnt.

That’s all fair enough it’s not about who’s right or wrong - but I too am following wondering what OP actually thinks is wrong? He knows his vehicle better than us so if it not right then fair enough. I presume MAF cleaner didn’t do squat?

Remember to write them down before you wipe them so we have something to compare to

Thanks for advice and all good points.
I am not sure it is broken so why fix?
I dont know it is not broken either.
The MAF screen looks a bit sooty which is why I was considering giving it a squirt of MAF cleaner.
The adaptive values were soooo different between banks that it looks suspicious.
My mpg went from approx 20 to approx 12 for no apparent reason.
It has since slowly crept back to bout 19.
Havent checked adaptive values since mpg plummeted.
Battery hasnt been disconnected for a long time
It did pass MOT so values cant be that too far out.

Going to try and check what the adaptive values are tomorrow after changing fuel filter

MAF could be faulty - possibly due to soot. Could cause mpg inconsistencies. Only way to check is with a known donor. I’ve heard of couple people open them up try and fix them it didn’t work so don’t do that. Could you try unplugging it see if it makes difference?
Filters good shout, and reminder for me

My twopenorth, for what it's worth.
Adaptive values are parameters that vary depending on many things (drive style, wear, service intervals etc etc)
Theory says that they should constantly adapt so should not need resetting. However, as these systems are computers, they sometimes get their knickers in a twist and resetting them back to a known value can sometimes eliminate a problem.
If there is a persistent "fault" that is causing the adaptives to be a long way out, resetting them won't cause a problem as they will just go back to where they were in a fairly short space of time.
The OP has two banks giving different values so in his case I would reset them then see where the values were after 100 miles or so.
Might be OK, might not but no harm in trying.

Also, the amount the values can adapt is limited so if there is a problem, they can only do so much to compensate before they "top out" so best to find out why they are so wildly different.

Never had time to check today
There is absolutely no chance of me taking it apart
Try again on way to work tomorrow

Checked adaptive values today and was reading -146 on both banks so guess all ok