fuel injectors

they are basically pretty simple devices,but very well engineered.
2 thousands of a second is the typical opening time.A solenoid that can open close in such a time period is a very accurate piece of engineering and they go wrong very easily

running a car

its an expensive  game,but spend a little to avoid big bills

collapsed CAT

A catalytic converter is a very reliable item but  they can collapse causing some major issues a quick of engine vacuum is a sure fire way of checking

thermal imaging

Our flir thermal camera is now one of mainstay tools for tracking  certain faults especially good for  looking at exhaust manifold branches for misfire detection