Audi A4 1.9 TDI PD 74kW fuel consumption problem

Hi all. I need your help. I bought Audi A4 with 74kW PD engine and I have a seious problem with fuel consumtion.
We know that this car may have consuption around 5-6 liters per 100km, but my car have around
8-9 liters. There must be some problem with the engine. I have a Octavia 1.9 TDI 66kW too, and there I have consumption around 5 liters. But I would like to ask you if you will know possible reasons.

Our idea was that there is problem in injectors, becouse engine has 260tkm. So we change the
engine head with injectors from good engine, but consumtion is still
same (other engine was same type and year).

Or have you some other idea why is consumtion so high? We have last
thing what we want to do, change the temperature sensor on the engine. But its last thing we have on mind.

Car is going well, no smoke. Of course, we used VAGCOM to diagnose the
car. There are no errors, only in measurments, engine idling speed is
little higher, 882rpm. When measuring the fuel injecting, on channel
008, there are three values in fields 2-4, which are 60,70,60 on 3rd
gear, 3000 rpm, full load. I think these values are about 1/3 higher
than normal. MAF sensor is 940, turbo 2162.

We would be happy for any tip you will give us where can be the
problem. Thanks much.