Hi,

So I have a 2002 A4 1.9tdi SE Saloon Redeye 130 which I've owned for about 7 years, milage is currently at 112k, 3 weeks ago I had a service including a new cam belt. The car is a manual gearbox and it's got the 70 litre fuel tank, so my questions are down to Fuel Economy,

I always fuel my car to the brim, and then run it down to about 10 - 30 miles remaining on the trip computer,

In my memory, my car always used to great fuel economy between 600 - 720 miles on a tank of fuel depending on urban / motorway driving, but over the past year it seems to have gotten steadily worse, my Miles per tank before the service was only 450 - 480 miles per tank of fuel, now it's serviced it is achiving a little more at 550, I always seem to remember getting between 600 - 650 without any real effort, but to achieve 550 miles I've had to drive carefully, never exceeding 2500 rpm, even the hour meter suggests I'm averaging 22 hours on a tank of fuel which always used to be around 25 - 26 hours a tank.

My car use has not really changed, I've driven the same route to work for the last 10 years, I even switched to branded fuel as apposed to supermarket fuel, but alas no real difference.

I have noticed when accelerating at night and another car is behind me, there is a fair amount of clear smoke coming from my exhaust which can be seen in their headlights.

At the service the garage reported no faults from the ECU. I've spoken to a few people and as you can imagine, have had an endless list of suggestions to the cause, from the inlet manifold egr valve, the airflow meter, to the turbo......

I have noticed even though the car still accelerates and I glance down and I'm doing 80 on the motorways, it just does not seem to have that torquey pull and response and feeling it had a couple of years ago.

Any ideas why the fuel economy is so bad, I feel like I'm loosing about £20 a tank in lost fuel economy, with the current prices Im happy to spend some cash to fix what ever is wrong. Problem is all 3 of the suggestions I've heard are not cheap, so which one is most likely to resolve my issues?

I don't really have anything to compare this data to, only my past memories, what sort of MPG are other 1,9tdi 130 BHP owners achieving?

Thanks for your help

Paul