I have a iveco tector 180e24 it has a misfire when driven at temperature ?

It has a misfire when driven and temperature is at 90degrees it also spits oil out the dipstick quite badly .it's loosing water but very slowly. There is no water in oil or oil in water it has me baffled. When truck is first started it drives mint .even when misfire starts there is no smoke out exhaust. Do I need new engine ? And if so I can buy one from a 2003 iveco tector same year as mine but mine is the 180e24 model and the engine I can buy is out of a 180el24 will engine be the same both manual gearboxs