On Saturday 1 November 2014, I had my Nissan Micra K12 checked out, with a second local mechanic, and he diagnosed that the car needed a new Coil Pack (of the four, No.3 was faulty) and when that was fitted, the car needed 1 new spark plug.
The initial 'fault code' was 0303. There was not a problem with regard to compression, which the mechanic said was 100%. The total cost of the work was €70.00.
On Wednesday (5 Nov 2014), the car appeared to be making a grinding sound but only when I attempted to accelerate. Then, on Thursday (6 Nov 2014), the oil light began to come on intermittently, particularly at start-up and occasionally when driving. The car appears to have adequate oil, so perhaps it's something to do with an oil sensor and/or faulty contacts on wiring.