l have the same problem as Francis P.The glow plug lights come on intermittently, some times accompanied by a loss of power.It usually happens when going up hill in 5th. l took it to a garage where they did a diagnostic test of the ecu.First they found 1. pre-heater plugs faulty or open circuit, 2. pedal sensor open circuit.From this they told me l may need a new throttle sensor, but they were not sure this would fix the problem.l took the car away, but the problems continued so l returned to the garage where another ecu test recorded a fault with the EGR valve.The garage told me replacing the valve would solve the problem, so l agreed to the work, but when l drove home from the garage the problem persisted.Is replacing the glow plugs really the solution?
Incidently, the problem started to occur immediately after l had the cam belt replaced.Could this be anything to do with it?

A friend had a similar problem with a Transit - was told faulty Lambda sensor. The light would come on and the engine stall. Turn it off and start it again and all was fine - until the next time!