over revving diesel/glow plugs staying on

[martings]

occasionally, i find that it takes a long time for the glow plugs light to extinguish before starting the car, and upon starting the car after this event, it over revs up to over 2k revs and drops back to normal tick over after about 5 secs.
Car has done 105k - FSH
Any ideas?
thanks
Glen

 

[dan_b]

Glow plugs need replacing?