As I described earlier, that during two-three back, I went to Universal Autos, Ichra Lahore, person did the overhaul of "Head" including change of Gasket, seals, Venchery and many more.
I have still same issue. I could not find any leakage in pipes, car works smooth on CNG but give problem on petrol.
I have few advices that also I am applying, I think even doing all such things, my conclusion is that there is ONLY setting issue with petrol nothing else.
I am still facing issue, but trying to find a good mechanic to do Petrol setting. Because if there was issue with "Head/seals" etc then car must have problem even on CNG. Lets see and pray that I could find a solution for this soon. Inshah Allah