Bad vibes... :(

[Genhawk21]

I have a 1984 Z24, stock. It has some kind of terrible harmonic vibration at idle that rattles everything and makes me feel like my head is about to explode. I just replaced the catalytic converter and rusted out tailpipe, and that made it quieter in general but did nothing for the idle-speed humming. The muffler shop didn't find any other exhaust leaks.

 

I've seen some posts about u-joints and vibration, could that be it if it's the stock drivetrain?

 

Despite all the various little things wrong with my truck, this is truly the only think I actually dislike, so I'd love to fix it...

 

 

[Skib]

is your idle speed to low? what rpm is your idle?

 

u-joints arnt turning unless your moving.

[datzenmike]

Check this yourself. Look at the exhaust pipe (front to rear) and make sure it is not touching any part of the motor/tranny or the body. The pipe should be held away from anything by hangers so it is isolated and won't transmit vibrations to the body. I've had the pipe move over from engine torque when under load and make a vibration too.

 

I doubt the U joints even if driving at idle speed. They are not spinning fast enough.

[Genhawk21]

It idles at about 1000 (no tach, but that's what it says on the emissions report) - it feels ok to me as far as the speed although maybe slightly high.

 

I'll get under it this weekend and make sure nothing is touching where it shouldn't... it could very well be that a hanger rusted and fell off or something! 

 

Thanks!