Vauxhall Vectra engine management light flickering

Oh how I hate the engine management light!
I had this problem a year ago and so I had the the wurl bar and flaps replaced which I got off eBay for £35 which sorted the problem at the time the car went into safe mode etc which indicated what was the problem but now the light is on again it's not such severe symptoms with no loss of power which tells me it's a different reason for the light being on.

Any way here's the symptoms
1. Engine management light flickers especially in gears 1-3 and stays on after 10 minutes of driving
2. When started a smell of exhaust fumes inside the car

In fact the car is running very well besides the above symptoms so if any body could give me a few ideas at what may be wrong I'd really appreciate it.