Driving I get a misfire for about 3-5 seconds?

Hey guys, I have a 1.5 sky active diesel cx3 2016 with 82k on the clock. The usual DPF flashing on the dash, but I think that's one of the exhaust pressure sensors. This car has just had the timing chain replaced as it was stretched, so I've done about 2,000 miles since the chain replacement, and everything was running peachy. I had this issue before as we thought it was the timing chain causing it so I guess not, when on a longer drive after about 180miles of motorway driving I get a misfire for about 3-5 seconds if I dump the clutch when this happens the misfire is gone the engine otherwise runs perfect then a engine management light comes on. This only happens on a prolonged journey of motorway driving, short journeys have never done this. Could the DPF fault be causing this or an injector, EGR etc. I'm thinking of getting the DPF mapped out. Any insight to what this could be would be invaluable.
thanks in advance.