Usually the gauge sweep is down to the battery, as the power is dropping, the dash does not get the power it needs and so does a gauge sweep and goes back to normal again, this is usually shown on start up though.

The clutch pedal switch IIRC is used as an input to inform when the clutch is down to shut off fuel when coasting up to lights etc and so better economy.

It may possibly be a faulty ECU?

Martin