Hi all, this 1994 Audi 1.9 tdi Avant, has a strange misfire only under load/medium throttle and mostly noticeable in 5th gear at about 1500 rpm. It can be felt in the lowe gears but much less noticeable, it feels like a cylinder cutting out(lot of vibration, gear lever jumping about) but without loss of power and returns to normal if you release the throttle and above about 2000 totally disappears, however very occasionally there is a stutter at higher revs, but has done this for a long time now, fuel filter is not that old, and there are no fault codes stored, I can't get it to misfire off load either. Had a look online and in the archives but can't see anything similar to this, wonder if anyone has any ideas please?