In my experience nearly half the mechanical faults developed by our vehicles are easy to fix. We should be getting some basic car fixing engineering training from the authorities: A certificate course that comes bundled with the driving license. Until that becomes a norm, we could try one idea.
The modern day automobile has a microprocessor controlled engine. So we are steering a computer while driving. If my mobile has a software on it that interacts with the microprocessor of the engine - via, say Bluetooth - and that application would tell me roughly what or where the fault is, then may be I could have a go myself. That could save me time waiting for the mobile workshop to come around.