Have you tested it in different gears to see if it is the RPM or the speed when you get the vibration? Have you tried jacking rear and running it up to speed without the car moving?

There is an excellent suggestion, I found this issue on another car that turned out to be the fan..

Ok I disconnected the Belt driven  Accessories. Still has a Vibration. Hand throttle at about 1/4 open and the Vibration begins. I can feel the Fender Vibrating. Continue opening the Gas and it disappears. I haven't checked the Torque Converter yet but if it was loose I would expect Vibration all the Time.? Harmonic Damper would continue once the Vibration started I think? It has not shifted and is accurate.  Any other Suggestions? I wonder if turning the Torque Convertor 1/2 Turn might make a Difference. Again I did not mess with any of the Engine Internals when I had it apart this past Winter so I am very puzzled about what is going on.

  

If you did not reinstall it in the same position, then turning the converter might be worth a try.  If the flexplate has a heavy spot and the converter has a heavy spot and you get them lined up, it would probably be noticeable.  Mark them with paint or a marker so that you don't loose track of where they were in relation to one another.

The damper is fairly small and close to the crank centerline so there is less chance that it is the problem.  I don't know how you would test that besides installing another.


Lawrenceville, GA

If I disconnect the Converter from Flex Plate can I run the Engine and perhaps better diagnose if the Problem is Engine or Transmission related? Is there any potential Problem doing this?

  

If I disconnect the Converter from Flex Plate can I run the Engine and perhaps better diagnose if the Problem is Engine or Transmission related? Is there any potential Problem doing this?     

Only trying to START the engine. You have the earlier F/M with the ring gear on the convertor housing don't you?

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You are correct. Didn't think about that.

  

Could it be that it is not firing on one cylinder completely and it levels out as the revs increase?

I  kind of wondered about that myself. I guess I could take an Extra Ignition Lead and Spark Plug and try One Cylinder at a Time and see if it makes a Difference unless You have a better Suggestion for Diagnosing?

  

Lisle 19380 Spark Tester

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