Anyone had issues with MPG dropping? Had been getting mid 50’s but only getting mid 40’s now in recent months. Same journeys daily and have tried different locations for fuel. Has been looked at by a mechanic but no issues noted. Car drives 100%. A6 40 tdi.

I have never got anything near to mid 50’s in day to day driving unless on long distance motorway trips.

I usually average 42-47mpg. Mixed bag of driving dual carriage ways, towns and villages. 
 

I always leave in auto drive select and never eco. 

I will try auto in drive select and see does this help. Can’t even get close to 50 even on long runs now which previously was no issue. Has been checked over by my mechanic and all seems fine and no fault codes

Run a can if Forte diesel conditioner through it, then change the fuel filter. When warmer weather arrives, fuel efficiency will improve. Run premium diesel too.