Urgent help needed, I have a 2008 Ducato maxi 160 3.0l with a periodic starting problem, it turns over but will not fire, there are no fault codes on the diagnostics and has been in a fiat dealer for the past three weeks on and off, some days it will start some not, it may start try 10mins later no start it is driving me mad anyone have any idea’s, the dealer has offered to replace all parts at a cost of 4k at my expense and then cannot guarantee a fix