Bro my car's (K6A) catalytic converter net has been already broken but I am also facing the same issue, crazy vibrates, cold start, abnormal accelerator. Engine starts with missing and then rmp goes upto 2.5k to 3k while driving. Car average is 8KM/ Litre.
I am based in Karachi and mechanics are making me fool. Changed engine assembly, injectors, coils, plugs. The problem remains the same. Now I am thinking of installing catalytic converter. Would that make any difference?