I have an Astra 1.6 8v V reg. This is hard to explain so I'll do my best.
My Engine Management Light comes on now and again, sometimes when I'm doing about 50 and have to decelerate going down a bank or accelerate going up a bank or slowing down quite quickly. If the light is already on it will sometimes go off again if I go down a bank. Some days it doesn't come on at all. I now nearly always know when it will come on and where.
According to a mechanic the diagnostic check came up as no fault found as the light doesn't stay on. (Apparently it needs to be on all the time.)
Anyone have any ideas because this is driving me mad.