Worn injectors can cause rough idle, as well as low fuel pressure(failing pumps), clogged fuel filter, bad pressure regulator, bad spark plugs (did you change these also?) Distributor cap can cause problems too.

Does your economy gauge work properly or seem to behave normally? I had a rough idle one day and it was because the line to the econo gauge fell off the engine.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)