The mechanic today diagnosed my car rail pressure with roughly around 15 psi (1.5 bars) and it should be around 30-40 psi (2.5-3 bars). He told me that it could be fuel regulator, fuel pump or fuel filter. All these parts and labor is very expensive. So my bet is on fuel filter, so can an old fuel filter be responsible for such a drop in pressure?
The symptoms for my car is that it takes 10-12 long cranks for car to start, BUT once started it runs fine. Which even makes me wonder why does it even runs fine when supply pressure is low but takes tremendous effort to start!
The car is 2011 mini cooper base model N12 engine.