Engine Hesitation - Spark Plug

This is field case trouble also one of my trouble encountered today as a technician. Some there are trouble that easy to think But its hard to find out when it come from, and also some trouble that its hard to think because of some other system that connected. But its easy to get where is this start, I have this trouble to day Elantra (HD).
 Model: Elantra (HD)
.Model Year: 2009.
 Displacement: 1600cc
 Fuel: Gasoline.
 Mileage: 40321km.


1) Trouble Condition:

1. Engine Hesitation When Start in cold condition.
2. Poor Engine power in warm condition.

2) Trouble Cause:

• Number 3 ignition coil cracked.  

3) Trouble Diagnosis:

1. Scan tool Check = No trouble found.
2. Inspect the engine condition with the ignition coil coil removed one by one.
   (engine Starting Condition)
   = Engine does not change when the # 3 cylinder is removed.
3. Inspect waveform using Scan tool.
   = Abnormal wave in # 3 cylinder.
4. Check all ignition coil.
   = Abnormal condition (Number # 3 is cracked)
   = After replacing the ignition coil, the engine operates normally.

4) Repair Guide:
    Replace the ignition coil # 3.