Ok, so i buy this 97 dodge 4x4 extened cab sport.  111k on the
odometer(360cid magnum, auto trans), body straight, paint good, engine runs
albeit a little rough.  Put in cap, rotor, wires, plugs, O2 sensors (both),
PCV valve, flowpro catback dual exhaust and a new set of 265/75/16 "more
highway than offroad" tires.  When I am going anywhere between 40 and 70,
there is a shimmy (it's severity comes and goes with no rhyme or reason as
to under-power/coasting,  engin rpm or speed although it is somewhat more
pronounced under load) that feels somewhat like a wheel out of balance or a
bent rim.  I took it back to the tire dealer, (Discount Tire) and they put
all 4 on the road force balancer and found two of them to be out of spec so
they replaced them.  The other two balanced out a zero, and none had any rim
problems what-so-ever.  I am pretty confident that the problem is not in the
tires or wheels.  The sterring is still very tight with no wander or
clanking and the vibration is throughout the turck and not in the steering
wheel.  What should I be looking at to find the cause of the shimmy?   It
gets bad enough at times (like triving on a washboard) that I feel ilke the
truck is gonna come apart.

Thanks in advance,

-Jerry