I drove on some rough road recently. ('99 Galant, 110k, 4cyl, 2.4L).
From vibrations ---- "buzzer like" screatching sound -- come from engine and for very short time check engine light appeared. Everything lasted ~10 sec.
Then everything went ok.
Autozone read no codes.
Few days latter, same thing happened...???!!!

Car runs perfectly afterward.
Does not sound like belt and belt related issues.

 

loose/corroded battery terminal.
or your batter isnt secured and its shorting on the hood, which will cause a fantastic fire/explosion.

 

well is the MIL-aka.(check engine light) still there? If so I suggest you try going somewhere that can look up this code...If you live near any community colleges with an automotive program they help many people out.
Secondly the vibration can be numerous things. Like Manybrews said it can be that which I hope it isnt.-That much Current rushing thruout the body of the vehicle may theoritically cause PCM malfunctions. So good luck trying to find out that MIL.

 

It's not battery.
Check engine light just appears for few seconds, went to autozone, no codes.
It's dynamic sound.... when thing happened I immediately removed my foot of the acceleration pedal, car started to slow down,
and the sound changed down with rpm's.
But, all lasted to short to try to do more.