[motornut]

I've seen the oil gauge jump up as the throttle increases(does it?)
i'd do the sender grounding check (checking for full movement)and
make sure the block is grounded good and
unplug the harness on the firewall and ohms meter the wires checking for breaks
there is a spot where all the wires go down to one ground back behind the cluster,might check that is ok,adding another ground seems to fix things(me bouncing gas gauge)