I have a 2.0 TDI 140 A4 cab 2007 and I'm currently only getting 35-40 mpg average despite my best efforts of driving with a feather light foot. I have noticed that the A3 with the same engine and age has much better MPG (55 on paper at least) does anyone know if I could remap or tune my engine to achieve better MPG? I don't understand how the same engine of the same age can vary so much between models.

Thanks in advance for any help

 

well for starters, the a3 and a4 are very different cars and the weight difference alone would explain some of it. idk about retuning the ECU but you could try a throttle body reset. search the forums here or google it, i do one every couple of months but im not sure if the procedure would be the same for your car (i have a 2008 a4 with the gasoline engine). there may also be a difference based on the drivetrain. quattro will use more fuel than the cvt no matter what, again a weight and power difference.
if you want a real comparison, you need to find the same exact car, not just the engine. after that, you can look at maintenance things like fuel injectors, fuel filters, etc.

 

The "on paper" MPG claims are always inflated. 35-40 sounds pretty dang good to me. You're probably not going to do much better than that with city/average driving.

I get 20-22 MPG pretty consistently with mixed driving in my 2.0TFSI A4 and I'm happy with that. It's much better than our Jeep which gets around 13!

 

If you live in the US 35-40 is good! I'm paying UK fuel prices and Diesel is £1.40 a Litre, I was expecting between 40-50 given that I do a 250Mile motorway run pretty much every weekend.

 

Thanks Dude, I have a day off work tomorrow so I will give that a go see if I notice a difference.
[EDIT]: After looking at this further I have discovered that Diesel cars don't have a throttle body so I guess this can't be my problem

 

yea i was afraid the diesel would be too different.

 

Never mind, I will keep looking for a cause. Thanks for your help.

 

I would check out some maintenance stuff like tires (do you have winter tires on? ) clean or replace fuel or air filters, clean off radiator or intercoolers, do you have the CVT or quattro? Can you reteach the tranny to shift more efficiently? Use the econ feature on the ac