Failing engine

It’s engine is failing while on a trip but once I switch it off and on again it will continue to drive fine. I always experience this when I’m in traffic that requires I remain startic by stepping on brake for a while when the gear is engaged or I’m descending fast on a sloppy road and did not accelerate but once I’m about to ascend and I try to accelerate it will fail until I turn off the engine and turn it on again.

It also happen sometimes when driving for a on a long stretch at a stabilize speed (100km/hr) and I decide to increase my speed and the the engine will seems its about going off and the RPM stick will drop to near zero until I turned off the engine.