So past 6 weeks my daily commute to work has dropped 7-8 MPG, from 38 MPG to 30 MPG, do 350 miles a week so having an effect on my wallet.

 

Nothing showing on VAGCOM apart from my SAI, car recently serviced, drop in MPG prior to service, MAF unplugged gives very similar results, but might make this a priority to change as its been 5 years.

 

Only thing that happened during this time was I bottomed the car with a big bang (blond moment with a drop curb), so I might have done something to the exhaust, what can i check on VAGCOM to see If I have upset something ?, Visually the exhaust looks ok, but could be out of site.

 

Your help would be appreciated.

Edited 11 October, 201411 yr by mluton

Have a look in Vagcom engine measuring blocks for the temp the ECU is getting from the coolant temp sensor.

Don't think there's anything in Vagcom other than lambda sensors that relate to the exhaust.

Edited 11 October, 201411 yr by pauldazzle

You probably already tried this but go with the simple stuff first. Go check your tyre pressures! Can have a big effect.

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Dragging brake caliper?

Have a look in Vagcom engine measuring blocks for the temp the ECU is getting from the coolant temp sensor.

Don't think there's anything in Vagcom other than lambda sensors that relate to the exhaust.

Yeah been monitoring the temp sender as I failed the MOT due to emissions this year from a bad sender, this was my initial thought to the problem, but checks out OK.

Dragging brake caliper?

Good call, will check this out.

You probably already tried this but go with the simple stuff first. Go check your tyre pressures! Can have a big effect.

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I checked them last week and they were a bit down all round, but pressures are holding OK.

Right then......................few weeks on.

 

Cleaned K&N Filter and MAF and been through 3 bottles of Redex and things have improved, Got 325, 346 and 357 miles from the last few tanks.

Since cleaning the MAF readings are more accurate on the display, I think I was paying to much attention to the display which was giving me way-over high false MPG figures previously.

 

With brimming calculating MPG, miles per tank figures are again better.

 

Still need to change the fuel filter though, but worried about "the clips", Lol.