Hi, if anyone could help....

4age 16v with cams and twin Weber carbs...

I have a flat spot in the rev range at around 2300-2500rpm, the engine stutters and struggles... Why?

Really temperamental problem. As in it comes and goes seemingly whenever it feels like it. I can't really see a relation to cold changes in outside temperature either.

Had a look at the spark plugs and the back set of Weber's are running much richer than the front set and have much more residual petrol sitting around the top of the set (checked that all the jetting is the same). Why is this and how can I fix?

Is this a timing problem, jetting, fuel pump... ? I don't know...

Any thoughts would be great...