Diesel Fuel Treatment/Reduced Fuel Consumption

[gould01]

Just had my car (A5 3.0 TDI) serviced and the Audi dealer recommended having the Diesel fuel treatment, however since then there has been a noticeable drop in fuel consumption i.e. 4mpg under the same conditions, has anyone else seen this problem ?

[Issac Hunt]

How many tanks/miles have you worked out the drop? Could be the colder weather or a change in driving style that's accounting for it? It shouldn't make your MPG worse.

Fuel treatment?! It's a con to get more money out of you IMHO. I've never used one and never had any problems at all.

How much did they charge and what does it involve?

[gould01]

Used 4 tank fulls now, approx. 2000 miles since the service, had the car since new and do the same 100 mile round trip four or five times a week, the car is in sixth gear for 80 of those miles and at 72mph (1800rpm) the car use to return anywhere from 44 to 48 mpg, now its around 40 to 42 if I am lucky. Treatment cost about £16 which is just a fuel additive, I spoke to Audi to see if they made any adjustments to the fuel management system or adjusted anythink and there reply was no.

[robtt09]

Colder weather will make a difference

[Tobez]

Have you checked your tyre pressure? even a few psi down from normal can make an appreciable difference.

[micheal balbrig]

Used 4 tank fulls now, approx. 2000 miles since the service, had the car since new and do the same 100 mile round trip four or five times a week, the car is in sixth gear for 80 of those miles and at 72mph (1800rpm) the car use to return anywhere from 44 to 48 mpg, now its around 40 to 42 if I am lucky. Treatment cost about £16 which is just a fuel additive, I spoke to Audi to see if they made any adjustments to the fuel management system or adjusted anythink and there reply was no.

Is it possible a poorer quality engine oil was used in service.
Best quality oil can often yield a few extra mpg.

[garboy1]

I had that fuel treatment not only did it significantly increase
Fuel consumption the car had trouble starting because
It sooted up my egr valve and and the car wouldn't run.
Audi A4 2.0 TDI 2009 sport line