i have a peugeot 307 1.4 52 reg and problems?

hiya the car was at first showing anti pollution fault and engine management flashing then said cat converter fault but i know this must be wrong as just had a new cat and full exhast fitted not long ago now saying engine coolant temp too high but the engine is not overheating as i've paid to have it diagnosed the computer said multiple misfires so i paid to have the coil pack renewed and also the temperature sensor also the esu was reset lasted half an hour now same problems any one have the same problems please?? also today had lots of white smoke