i have a ef i6 that has a rough idle and choppy until about 1400 rpm then its fine its intermitting but does it more often than not, seems to be after idling it does it worst, i have changed fuel pump and added new fuel with injector cleaner, changed plugs leads and coilpack and checked the seqencer for alignment, changed the ecu relay and ecu, checked cam timing, changed the tps and ics, i also ran a daignostic check and came up with system ok, any ideas cos i am fresh out and it super frustrating, any help on this would be apreciated, cheers.

could be injectors

try unplugging one at a time while engine running to see which cylinder it the culprit

tried that mate i could hear the engine cough taking the wires off one by one.

problem solved, i sold it.

ha, thats always the best fix