The most common cause of this behaviour is a build-up of air inside the braking system. When you push the brake pedal, the fluid is forced to push on the parts of the braking system that clamps the brake pads to the brake rotors. That creates friction, and that causes the car to slow.

But the whole system relies on that pressure and it works because the brake fluid (as a liquid) can not be compressed. But air can. So, if there’s any air that has managed to enter the braking system, it will compress when you push the pedal, and the clamping force at the rotor will not be as great.

The fix is to what’s called 'bleed' the brakes. This process removes the air and should restore braking performance. In the meantime, the absolute best advice is to not drive the car anywhere while the brakes are not in top shape. The consequences are not worth thinking about.

Have the car towed to a workshop and while it’s there, think about having the brake fluid replaced as well as having the brakes bled. Fluid should be changed every couple of years but this is a somewhat ignored procedure among many car owners.

This version of the Ford 5.4-litre V8 is not universally admired by mechanics. It can tend to run hot, and it’s quite common for this unit to suffer from stretched timing chains, worn chain tensioners and guides. Any problem in the area of the timing chains can lead to a misfire or stumble, and it can be worse when the engine is hot and the oil pressure that powers the timing chain mechanisms starts to fall away.

The best advice is to have the car electronically scanned. This might pinpoint the problem by throwing up a fault code that a mechanic can decipher (including the camshaft timing fault we’re talking about). Don’t continue to throw new parts at the engine; that’s a great way to waste time and money and still not fix the problem.

When you say you have fuel, spark and air. How sure are you? These are not complicated engines and given all three of those things are present, the thing is kind of obliged to run. For instance, while you might be able to hear the fuel pump running (suggesting that fuel is being supplied) have you checked the fuel volume and pressure at the injector rail? Similarly, while there may be power at the coil packs, are the spark plugs actually doing their job?

Beyond that, you need to start looking for an alternative problem and, in engines like this one, you’d probably start with things like the crank-angle sensor which supplies information to the computer to allow the engine to fire. If this – or any other – sensor is dodgy, it can put a stop to play. An electronic scan might reveal more clues.