Sudden drop in fuel economy- BiTdi


Registered User
My bitdi would happily return 44mpg on an easy run on the motorway and mid to high 20's local and being remapped it was fine.
Over the past 2 weeks its dropped massively to around mid to high 'teens and last night i struggled to get past 34mog whilst doing around 60mph !
This is really bad and wondering what could be the main issue for such a high drop in mpg.
Any idea's appreciated


Registered User
Is it possibly stuck in DPF regen mode? that would effect your MPG.

Or maybe a dodgy MAF sensor would cause in increase in fuel usage.

Let us know if you find a solution.


Registered User
VCDS Map User
Gold Supporter
You didn't have any new tyres fitted did you? Also check the engine hasn't been overfilled with oil, believe it or not that can cause mpg issues.


Registered User
Well... DPF regen was last done 12.45km ago and no failed attempts in the log.
Rear pads need doing but no light on yet and not feeling any excess drag /noise
Oil is spot on and was changed around 3k miles ago.
Tyres are new but were changed last year.
Not had a chance to log any maf readings
Thanks for the tips so far