1989 Mazda 626 excessive vibration at steering wheel at idl

I an a retired mechanic, but this one has me stumped?
All Igniton components and fuel system O.K. Vehicle
has good to exceptional performance on the road for a 2.2L 4!
My next option is to try replacing the trans mount and upper mount next to the timing cover.
Changing the idle speed does not help?
Was this a problem with this year model?