[padresag]

run a higher octane of fuel or retard your timing until it disappears. sounds like your eng is more than likely pinging and it transfers the vibration into your steering column. you also have some wear in some places i the strg column, but that wear in those parts come to life when the eng pings under load of the throttle. if you gear down in that instance the problem should go away as your eng is in a higher rpm range and you are not lugging the eng
ron