hi۔ i have exactly same issue. So far repaired throttle body coin, changed iec valve on thottle body , got the car scanned by electrician
Car vibrates with rpm dropping when speed reduced after driving 5 to 10 mins, same happens when turbing on head lights or indicators, car is Cultus VXRi 2011efi euro2
If anyone knows how to get it fixed please do let me know .