Drove to work on Friday and she was spluttering a little bit (particularly) when there was little throttle. One my way home it started doing the same but then died and wouldn't start. By the time the patrol man arrived it started (engine cool), I got another 10 miles before it cut out on me again which meant I had to be recovered because there was no spark from the coil

.
I started the engine again tonight thinking it would splutter n die again when the engine got warm but it didn't.
Any clues as to what could be the root cause? I believe the Hall effect sensor can start to play up when hot?
(Engine is a DJ 2.1)
Cheerz