CHECK PLUG WIRES...
CHANGE THE PLUGS IF IT RUNS MORE THN 30000 KM..
CHECK THE DITRIBUTOR TIMING... I THINK IT MUST BE MORE ADVANCED... IF IT IS THN RETAIRED IT..
USE CARBURATOR SPRAY N CLEAN THROUGH THROTTLE BODY...
CHANGE THE AIR FILTER N OIL FILTER
SWAP ENGINE OIL WITH ZIC A+...
IF THE PROBLEM STILL OCCOURED...
THN CHECK ALL SENSORS R PROPERLY ATTATCHED WITH THE CONNECTORS OR NOT... OR RE-CONNECT IT AGAIN... SPECIALY CHECK THE TPS SENSOR...
....
BUT SPECIALLY I DOUBT ON UR PLUGS WIRE...