hello,i've a 1991 k10 1.2 that had a fault.any advice would be much appreciated.i'm changing down thru' the gears & braking;when high revs develop.i stop & go into neutral;the revs lower.i set off again;uphill with loss of power.i stop,switch off engine for a few minutes.switch on again;low power on level ground;so i assume it's the clutch...