I recently bought a 1.8 TDCi 07 with 71,000 miles on the clock and I'm pretty sure something isn't quite right with it. I reset all the computer when I got it and I seem to be getting only 33.2 mpg average and around 400 miles from a full tank from mixed driving. There are no lights on the dashboard but I plugged a code reader in and found 2 codes in the ECU; P0299 - Powertrain & U0423 - Network. I don't know if these are contributing to the problem or just old codes that have never been removed.

Any ideas guys?

 

Hi Jonny I have the same issues as you I believe geting around 35mpg and very sluggish low down in the revs although seam fine at everything else my car is a 2009 1.8tdci with 70000 I jst thought that's how the were until I drove my mother in laws 55plate 1.8tdci what has 110000+ on the clock and it had bags of power and does 50-55mpg
Really need to fine out the issue as there is clearly something funny goin on I will keep you posted if I find anything please do the same thank adrian

 

I think the problem I had is different to yours. My problem was that some muppet serviced my car before I got it and forgot to plug in the sensor on the fuel filter. Fuel economy has shot up and just had a weekend away to Brighton and there and back got an average of 53 mpg.

Does your car make strange noises or smoke a lot when setting off?

 

The P0299 code could be the problem. It means you don't have enough turbo boost.
Could be a leak in a turbo hose, but it could also be a turbo problem or something wrong with the way the boost pressure is controlled.

 

Nope no smoke or noises that's the thing that I carnt seem to understand other than the lack of power and fuel consumption the car seems fine all pipes seem to be fine very strange