2001 Honda City Fluctuation-Engine Shut downs

The problem I am facing is as follows:

Early Morning:
Symptom 1
I start the car and it stars fine but as soon as I start driving it, the engine turns off and does not start and backfires when I try to start the car, the car starts after a rest of 20-25 minutes. (No engine check signs).

Symptom 2
Sudden loss of power while driving which shuts down the engine and even the car clock resets, the car starts immediately when ignition is given. (No engine check light).

Attempts:
Checked with electrician and replaced the distributor. (Fuel flow is alright)


After Attempts:
The car starts fine early morning, no backfires, no shutting down.

While driving the car the headlight fluctuates (electrical power fluctuates) which shuts down the engine. (No engine check light). The car starts immediately when given an ignition.

Please tell me what to do more, fuel pump is ok, fuel filter is ok