firing

firing on all (four) cylinders working or functioning at a peak level.

☞ This expression is a metaphor from an internal-combustion engine: a cylinder is said to be firing when the fuel inside it is ignited.

2004Natural Health Winter bugs usually strike when it's least convenient, so ensuring your immune system is firing on all cylinders is essential.

in the firing line in a situation where you are subject to criticism or blame because of your responsibilities or position.

2001Sunday Business Post Once again the International Monetary Fund is in the firing line after the financial collapse in Argentina.