Buzzing Vibration at 2000-2500 RPM

'92 3.8 with 193,000. Have fixed my window problems,just had AT rebuilt my a very reputable man, and on Tuesday I put on some spanking Toyo 800's. Well, it ain't riding like a Lexus, but it sure beats the AquaTreads!!!

Now, I notice, especially when first taking off while "cold", a vibrational buzz expecially between 2000 and 2500 RPM's. I can feel it in the accelerator pedal. IT is not a steady buzz. It has a cadence to it. Sort of like this ZZZZZZZzzzzzzZZZZZZZZzzzzzZZZZZZZZZzzzzzz...

Could something be loose from the AT work? Where would you check?

Did it make the noise before the tranny was rebuilt?

I'm 95% sure. Remember, those Goodyear Aquatreads I just took off were extremely rough, noisy, etc. I'll talk to the AT guy.

It does it in idle. "Not" a AT problem? Much more pronounced when motor is cold.

I think I am getting somewhere. Since it is much more pronounced when cold, I have come to the conclusion it may be a fluid related problem. When fluid is cold, more pronounced. Flluid gets hot, less pronounced. Am I a detective or what?? Matter of fact, I now believe it has to do with my power steering. There appears to be vibration from the reservour. ANy ideas from this hypothesis? Also, it doesn't do it every single time. Just 90% of the time.

could it be a wheel bearing? I changed wheels and tires on my silhouette and soon after a wheel bearing started buzzing.

Just a thought...
take it through some curves and see if the noise is more dominant on one side.