I've fixed my bucking several
times with one of the following:

loose temp2 sensor
excessive spark plug gap
rotor
cap

I would venture to say that
each occurence of bucking
may be caused by a different
component under different
circumstances.  We all get
too busy looking for the
ONE fix to the ONE problem.
If the bucking is a sharp
buck (usually what's
implied by 'bucking') it is
probably electrical (a miss).
Replace the maintenance stuff
first - plug wires, cap, rotor,
plugs..

Good luck,
Christopher Darilek