Lambda sensors boys and girls.
The are fitted to the manifolds of cars, and measure the concentration of oxygen remaining in the exhaust gases when they are released from the cylinder head. The sensor then sends this info to the ecu of the car which then decides if it is running too rich or too lean and then adjusts the fuel/air mix accordingly. Oh and all digis have them afaik, so it's not that newer technology.
Damage to these, can not only cause damage to the car engine by giving false readings but can also cause your catalytic convertor to fail. So lets say a lambda probe is about £40, and a cat is say £230ish, then there is fitting, which can be say 2 hours to remove all the manifold and surrounding gubbins, you are looking at about £350 for repairs.
Drop in the ocean then.
