[RFI] ignition noise in Chevy engine

[Dave NØRQ]

Ignition noise in my 2 year old Chevy Express van is quite bad --
Vortec 6L gas engine.  It is worse on 15m and upper HF bands,
but still bad on 6m, and detectable on 2m.

What would be the best place to start -- putting braided shield over
all the spark plug wires, or putting DX Engineering RFI Suppression
beads on the spark plug wires?  Neither?  Both?  Or better wires
or plugs?  Or something else?  The dealer won't fix it -- denies 
it is a problem -- and my fixes have to be somewhat non-intrusive, 
so as to not jeopardize the warranty.

Thanks,
Dave NØRQ