My 2001 A170CDi has been running really, really noisy of late, tick over is very uneven, lumpy, like running on 3, like a "donk, donk, donk" kind of thing. when on the highway it goes well, smooths out and cruises all day at 70MPH+ Acceleration when passing is good for a diesel too.

Fuel consumption is very good, not using any water or oil and no smoke. No fault codes on the reader.

Looses a bit of ATF but that seems to be from the breather on top of the box which I have extended and fitted a foam filter and seems to have cured that problem. still cheaper to top up the ATF than get it repaired, for the fourth time.

Starts right off the bat every time but very lumpy, like off balance rather than overall rough.

New air filter, had to replace #1 & 2 injectors as they blew and the idiot mechanic lost the little ball bearings and seats when cleaning them but the numbers are the same. Can't get # 3 & 4 out, solid!

Run injector cleaner in the fuel a few times, no change.

Only none standard thing is I blocked off the ERG ages ago, hasn't failed the annual test, in fact doesn't make any difference at all on the readings, just no crap going into the inlet manifolds.

Any informed advice would be very welcome, apart from take it to a dealer, that would write it off I'm sure.