Loud vibration

[Guest]

I am sitting in my car today in my school's parking lot and for some reason I decided to rev it up a little, only to 2000. As the engine goes back to idle it starts to make this really loud vibration sound, it keeps doing this at idle, for a grand total of about 3ish seconds. The whole car was shaking, my passanger claimed it was coming from his side but i couldn't pinpoint it. Later I drove the car home with no problems at all. So I have no idea what this was, I did some searching and maybe it was the balance shaft belt??? (The car was in neutral, with the A/C on if that helps any)

 

[CrazyM]

I know when when the balance shaft is out of phase and you rev\drive it, it vibrates a rediculous amount. If it was your balance shaft belt that broke than you should check that ASAP. A large amount of timing belt failure's are do to the Balance Shaft belt braking and taking out the timing belt.

 

[crimsondragon]

I'll bet $10 that your RPMs dropped to around 500, giving you that vibration. That usually happens when you have your A/C on. The load wasn't compensated quickly enough by the ECU. It could mean your ISC is going out the door.

 

[Guest]

I just got in my car and started up it is running fine and i couldn't recreate the event like earlier, although i am now noticing a bad vibration when i am reving steadily at 2k rpms