Honda civic 07 cdti. The accelorator pedal just seems to turn off completely, would anyone have any ides?

Recently whilst driving my car, seemingly only in cold temperatures, I get to about 3rd gear and the accelerator will go dead. No revving at all, the engine will stay on but start to splutter a bit. If I pull over it will continue to splutter unless I then push the pedal at which point it stalls. If I don't push the pedal it will keep choking and a lot of smoke will come out of the exhaust, after a couple of mins at idle it will seem to start working again, but for only about 20/30 yards. Also if I don't pull over when this happens but turn the ignition off and then on again so quickly the engine doesn't turn off, it will seem to reset again for another 30 or so yards... I have had problems with the egr before and did have it mapped out and have also had a re map on the car ( not a massive one, more economy than speed ) but these problems have started a good few months after any of this. I'm really at a loss as it shows no error codes and has not done the problem once in front of any mechanic, so I keep getting told nothing can be done... help would be very much appreciated
Thank you
Matt