Knocking and******** engine

I have hundai accent viva 1.6 dohc petrol 2002 model.
due to monsoon season engine make some misfire and find some load when a/c is on and headlight is on and in running feel knocking and********. So pleae show me right way to repaire advice. Thanking you. Zaveri
my email. Zaverizaveri@yahoo. In