Brother, my car (vitz-2008) also does the same and even engine check light turns on after driving for 10-15 KM. Regarding the engine check light also my observations are that now a days in morning since the temperature is down so it doesnt turn on in my whole ride of 55km (1:15 Min) to my office while on way back home in evening (4:PM) it turns on after 15-20 KM. so far i have applied the remedies but the vibration and check engine problems are there
1: Did complete tuning and cleaned/checked all those sensors/plugs/throttle etc that are suggested in various threads for this particular problem.
2: Rest the ECU through battery trick
3: Did computer scanning and removed error codes
4: Using high octane and normal fuel in 60-40 ratio.
Kindly share your suggestions/remedies please