Stupid question, have you scanned for codes. Like with a scan tool?
I had a similarish problem with an 18 nv200. Dead pedal while driving down the highway. No cel. It did it totally randomly. Did it once one day. Driver pulled over, turned it off, restarted it and carried on the rest of the day without problems. Slowly it started acting up more and more. I scanned it and there was a code for the throttle sensor in the throttle body. Took it to the dealer, they replaced the throttle body, on my way back from picking it up it acted up again so I took it back again. This time they replaced a throttle control module. Van was fine for an entire year almost to the day....Then the exact same problem came back. Van was off warranty by now but they offered to take a look anyways. They couldn't figure it out and ended up replacing the entire engine harness. It's been good for about a year again so far..
View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 37.7 mpg (US) ... 16.0 km/L ... 6.2 L/100 km ... 45.3 mpg (Imp)