2004 Vauxhall Vectra loss of power engine managment light coming on

you will have an engine management fault. when this is detected by the engine control unit it will restrict engine performance to a level where you can get home or to a garage. re-starting the car resets the ecu allowing you to drive normally again until the fault shows itself again. sometimes this can simply be low engine oil level so dip it and top up as required then give it a run to see if it worked. if not let a garage take a look possibly read the fault codes in the ecu and give you a diagnosis as to the fault.

Hi. I'm new to this site but i had the same prob with my zafira Dti. It sounds to me like yor EGR valve is at fault. Very common prob with this car. The Valve gets clogged up with carbon and crap from engine and doesn't open correctly. It can be cleaned out but it can be tricky as you run the risk of some of the crap falling down into the valves. I went for the easy but expensive option which was to replace the valve. but this costs about 200 quid. but at least i had the piece of mind that it was clean.