Sport Ka heavy Fuel usage

[Stillwaters69]

Hi can anybody help,

Ive modyfied my Sport Ka with a kit from steve wyndam racing - 4 branch manifold - fast road cam - unichip ecu - no cat.

Now the KA is using loads of fuel - im lucky to get 24mpg - the garage had it on a diognostic and said the cars mixture was all over the place not knowing if it should run rich or lean but mostly rich with low oxegen.

Ive thought about changing the no 1 lamba sensor in the manifold.

Anybody got any ideas please ??