Technical Fiat scudo 2008 multijet misfire

[Chrisbris13]

My fiat scudo has created a misfire on start up. Lots of pal blue smoke until warm, smoke stops but still slightly firing wrong.
Have replaced 4 injectors and egr valve.. Removed particulate filter and cat. ( god knows why it was the garages idea ). Anyway £1200 later still no better, in fact probably worse, however after the smoke clears and it's warm it pulls like a train and is now more economical . Has anyone come across this on their scudo/expert/ dispatch? If so please I'm open to all opinions. I
Just want it fixed but now don't know where to start . It's having a compression check, but I'm
Confident all is well and it really does pull.......
Thanks all awaiting patiently...

 

[Edtheted]

Hope you saved your DPF and CAT as you'll need um to get through your next MOT the Gov. changed the law including them into new MOTs?

 

[Andycabs]

Could be worn/fractured piston rings