25-07-17, 08:32 PM
Did you check the connectors and loom in the tail?
I had an occasional misfire that was impossible to track down until it cut out permanently on the motorway one night… turned out to be one of the link plugs, or rather a wire to it, had chafed against the frame and got cut.
Another common place for the same sort of issue is the wiring to the ignition switch as this has to flex with the steering.
My guess would be the former though if it's only the sparks dying and not all the electrics.