Exactly same thing happened with me yesterday on motorway. After 60-70km car won't take acceleration and sounded like carb fuel level is over and/or its on choke.
After rest of 5-10 minutes it woks fine again. This happened 2-3 time and after that I removed rubber from air filter so it ca get more air and it didn't created this issue after that till I reached lahore (100km).
I recall that mechanic increased the mixture last week due to which it emits black smoke at startup. So I will probably decrease the mixture and get it tuned on petrol as CNG is not available these days.
Mechanic asked to open up carb and do full tuning but I do not trust when it comes to carb opening. 