I have old Suzuki mehran 1990 model recently it has been performing badly. The car start jerking and stuttering after 2-3 km drive and it's performance decreased uphill and the jerks increase. Sometime the engine shuts down.. I have recently changed the coil, fuel pump, got it tuned, the mechanics say that the plugs and plug wires are OK. Fuel filter is new one also... What else can it be...
