My car was doing minor missing with a light foot and at constant speeds. So I got the carburetor serviced. My mechanic always say not to replace fx carburetor jets with the kit you can find in the market. That just kills it. I luckily got a brand new carburetor few years back when someone I knew was closing his auto parts shop and he found of those lying in his shop.
If you are in Lahore maybe you can give a visit to Nadeem at Madina motors punjab society. I hope he can help you in that. Some people say he used to be good when he worked himself. But carburetor is still something he does himself. So I always get it serviced from him.