Hi all, my name is carl. this is my first post and im desperately looking for advice.

I have an 08 Audi A4 2.0 tdi convertible with only 24,000 miles on the clock.I ran the tank quite low on saturday down to 25 miles remaining on the range calculator.
the following day as i first drove it i noticed a lack of power. i only got 2 minutes around the corner when the car stalled and wouldnt start.
other than low fuel there were no other warning lights on the dash.
i put around 12 litres of diesel in it and tried to start it but it wouldnt go.
The RAC came and tried to blank off the EGR valve but this didnt do much.
today they returned with a new EGR valve but this still didnt fix the fault.
there were no fault codes showing on their diagnostic machine.
they now say it might be the dpf !!
Im wondering how it can be the dpf when there are no fault codes and no warning lights on the dash and the mileage is quite low?
Could it be that my car has ran out of fuel and now has air in the fuel system? I would of thought the RAC would have thought of this first and tried to bleed the system or something.
Currently my only option is to try a local independent specialist and hope they can diagnose the fault before i spend a small fortune on parts i may not need.
Any help or advice would much appreciated.
Many thanks in advance.


Carl.