Try that and see if it works

[obi_waynne]

I really hate the garages who fix problems by trial and error.

I'll sell you this random part, and charge you to fit it and if it doesn't solve the problem come back and we'll sell you something else that might work?

Is this fair? Is this the nature of cars? Could better fault diagnoses be found? Is this a strong case for going to a main dealer or specialist who knows the car well.