2005 Peugeot 307 why does my car run soooo bad at the start

Engine Performance problem
2005 Peugeot 307 4 cyl Two Wheel Drive 28500 miles

have had the car for about 2 years been ok last time I had it serviced was 10 months ago and ever since then been running bad its like it is misfireing and loss of power and then kicks in and drives, but when I stop, it some times starts to do it again driven me mad 1.4 pertol dont know much about cars the so hope I can get an answer here
and the noise that comes from the engine some time when it does it sound bad it like jurks and backfires so any help would be welcome