Have check ignition, plug, and leak but not able to find the cause. Rpm drop when air cond on 700 to 500.
Check voltage is ~13.6 from alternator. Sometime but not many voltage drop to 9v intermittently. Not sure due to this cause idle shake. Headlight open rpm increase bit and less shake when on D mode, N mode rpm still will drop intermittently.
Check with obd2 no error code. Alternator heard Yiiii sound but very low sound like a pin spin around metal.
Idle rpm drop still unknown.
Please advice.
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