[NI_Volvo_Nut]

I have a 740 with similar symptoms however always starts. I suspect a leak on the injection pipes but in my 20 years of ownership I haven't checked them properly lol

TBF I only came up with the theory recently after actually sitting down and working the system out, it seems to work very similar to a diesel in that it needs pressure to make the injectors "pop" therefore a slight leak allows pressure to drop in the line thus not allowing that injector to fire until pressure is regained. MY other theory is a leaking injector which is washing the cylinder walls and taking away compression until the oil is replaced.