Engine Abnormal Vibration on Idling,matrix

Another Trouble that for me to Explore, This trouble cause by loosed terminal ground and injector.
Model:Hyundai Matrix(FC).

Year Model: 2006
Mileage: 130782km
Fuel: Gasoline
Displacement: 1600cc
T/A: Auto
1) Trouble Condition:

• Engine Abnormal Vibration on Idling even the engine cold or hot condition.

2) Trouble Cause:

1. Due to Loosed ground terminal and clogged injector 1 & 4.

3) Diagnosis:

1. Scan tool check:
   = TR Switch
2. Check current data of engine:
   = some sensor indicated that not supported.
   a) Oxygen sensor.
   b) map sensor.
   c) coolant temperature sensor.
   d)battery voltage.
   e) data of injector is 13.5 (Abnormal)
3. Check the current data of TR switch : Normal operation.
4. Check compression test: Ok with in  specification.
5. Check spark from spark plug: Ok
6. Fuel pressure test: Ok
7. Visually check up.
8. I was observed that if the engine is running the main relay getting abnormal hot and visually Check that all terminal wire seems like melting indication that also terminals getting hot.
9. Check all wires, socket terminal and ground terminal .found out that ground terminal beside the TCM(Transmission Control Module) loosed.
   = Re fixed it.
10. current data of engine operated normally but the engine vibration still occurred.
11. Actuation test: Ok of some sensor, But from injector there is an abnormality in actuation the # 1 & 4.

4) Repair Guide:

• Re-fixed Ground terminal and clean terminal connector with electronic spray cleaner.
• Replace injector 1 & 4. = As a result the engine operated normally.