Hi all

I have searched the site and have tried several fixes for vibration/shaking/bukcking. Unfortunately I did not find anyone wih the exact same problems I am having. Mine is speed specific and not rpm specefic.

I have so far replaced the wires with Beldon units, changed to Autolite plugs, swapped 3 known good coil units in from donor car, and then found the drivers side front hub bearing to be slightly loose but not noisy so I replaced it. The shaking is still there.

It will start to shake at round 45 or so and get real intense around 52 mph. It does it in either 2nd, 3rd, or 4th gear. I think in 2nd gear the engine is running about 3500 rpms appx. It does not shake if I am coasting, I need to be on the accelerator, even just slightly. I had a scan tool hooked up (Snap-on MT2500) and it showed 0 mis-fires and 0 history misfires on all cylinders.

What trim is your 01? Please add it to your signature.

Generally, vibrations that start around 45 mph are caused by tire or tire balancing issues. You may want to have your tires checked.

If you have a hill near by put the trans into Neutral and coast to see if the vibration is still there.
If it is its chassis or tire related, if it goes away its tranny or engine related.

He'* saying, "vibration/shaking/bukcking folks. What does tire imbalance have to do with bucking?

bukcking??? I crack myself up.

As you understand it, nothing. But tire balancing may resolve his problem.

That is because people are not always precise in their understanding and use of words. And since he used all three words, perhaps he does not understand the word "bucking" in the same way that you and I might. That'* one of the things that makes diagnosing real-world problems in a text-based environment difficult.

Let'* help by saying that bucking is generally understood as a sharp jerk that occurs in a random manner (irregular frequency) like the last kernels of popcorn popping, and differs from a vibration that occurs with a more regular frequency (like a massage chair). Shaking of the car can be produced by either vibration or bucking.

While bucking is often caused by an engine miss; vibration or shaking, especially as described, would be more likely a balancing issue, like a wheel, or bad drive axle.

Touche Bill.

Thanks for all of your replies and ideas.

The problem turned out to be a bad driver side half shaft. I think the inside joint was bad and could not flex as much as it should. It was weird because I never heard any clicking from a failed joint to point me in that direction either. I recently had to replace a half shaft on my 96 Bonneville also. It too was a strange one as it never clicked or acting like a typical bad half shaft. What this was doing was howling and it sounded and acted just like a bad wheel bearing. Just goes to show what a chalange they can be.

thanks again
Andy in MI