My XTX had been running a bit rough and misfiring for a few days, gradually getting worse.
It would run fine for a few minutes and then misfire really badly, then calm down again.
It got to the stage where I had to hold it at around 4000rpm when stationary to keep it running.
Eventually the motor died and all dash displays went out as I pulled away from a junction.
I turned the key on and off a few times but everything was dead.
The battery leads were still connected, but I happened to push the white connector on the thin black lead from the battery earth and it clicked together. When I pulled on it, it came apart very easily.
It looked as if the connector was together but it was apart enough to cause the misfire.
I had to prise the lugs apart a bit so that when the connector was pushed together it stayed connected.
May be worth checking your connector first if you have a misfire.