Need Help with Strange Vibration

[Seadweller]

Thanks guys...What puzzled me is that the vibration isn't there 100% of the time. I've been in the car several times trying to replicate it, and it never appeared, which is why I questioned him to begin with. This time, I was in the car with him for over an hour, and for nearly the entire time, there was no vibration at all. I was about to refer him to a psychiatrist, when the vibration just appeared out of nowhere while sitting at a light.

Would a bad motor mount cause an intermittent issue like this, or would the vibration be present 100% of the time?

[tommy583]

If you notice the RPM isn't steady when the vibration happens, try cleaning the idle control valve. It is on the side of the throttle body. But as I reread your post it appears the RPM's were steady, so I will third the motor mount.

[RobertKing]

Originally Posted by Seadweller

Thanks guys...What puzzled me is that the vibration isn't there 100% of the time. I've been in the car several times trying to replicate it, and it never appeared, which is why I questioned him to begin with. This time, I was in the car with him for over an hour, and for nearly the entire time, there was no vibration at all. I was about to refer him to a psychiatrist, when the vibration just appeared out of nowhere while sitting at a light.

Would a bad motor mount cause an intermittent issue like this, or would the vibration be present 100% of the time?

This sounds more like a fuel issue to me. Sitting at a stop, there is no suspension or road issue at hand. So, odd vibrations are motor related. This leads me to poor fuel quality. Could be a knock sensor timing issue.

[Geof3]

Originally Posted by Seadweller

Thanks guys...What puzzled me is that the vibration isn't there 100% of the time. I've been in the car several times trying to replicate it, and it never appeared, which is why I questioned him to begin with. This time, I was in the car with him for over an hour, and for nearly the entire time, there was no vibration at all. I was about to refer him to a psychiatrist, when the vibration just appeared out of nowhere while sitting at a light.

Would a bad motor mount cause an intermittent issue like this, or would the vibration be present 100% of the time?

Depends, if the MM is shot (I promise you it is with that mileage if it’s original) it’s possible that another issue causing a vibration is felt more. So no, most likely an intermittent vibe isn’t going to be caused by the MM but a dead MM can potentially be felt for sure at idle. Especially if the center rubber has completely detached, which is very common. Basically the front of the engine is sitting low, and on a slightly damped chunk of metal.