Check Injector sign/loss of power

Hello,We have a problem with our Grand Scenic 1.9dci 55 plate which we have had for about 3 weeks. Check Injector light keeps popping up on the dash(like a few others on here have said) but everytime it pops up i lose power,its only when i stop at traffic lights etc it will go out and the power returns.However i noticed last night when the light appeared and my power went if i knocked it into neutral then back into gear the light would go out and back to normality again with the power.

I know it could be a variety of things,but i thought i would come on here and ask if anyone has any ideas?

Any advice would be a great help !!