My Mazda 3 keeps loosing power then cutting out when I slow down

HI,. My Mazda 3 keeps loosing power then cutting out when I slow down.
Then take a few tries to get started again (with no response from the accelerator) . When its running it seems to chug at times but then other times its as if the turbo wants to kick in even though I'm holding continuous speed. Its just had 4 new injectors and a cam sensor which has not solved the problem. Have you any idea what the problem could be?

Thanks