Can be one of several items.
- When it quits, if it won't engage the starter at all until it has sat awhile, but when it finally does engage the starter, it starts right up, I'd say it's a bad Engine control relay on the RCM or fractured solder on the RCM. Send the RCM to DJ in Arizona for repair or order a new one online.
- If it quits and will engage the starter and crank but won't start - I'd change the Crank position sensor.. IN this case, it could also be a bad fuel pump relay on the RCM but I really doubt that.