2003 Ford Focus Pricing and Specs

You’re talking about two distinct models of the Ford Focus, so if there’s any interchangeability it won’t be much. Perhaps there would be some mechanical parts in terms of the engine, but the 2007 model was a physically larger can than the original (2003) so even things like the suspension units and brakes are unlikely to be interchangeable.

As for body panels and interior fittings, I doubt there’d be any interchangeability at all. The later car had different panels and the interiors were also completely different. Changes to styling also mean that headlights, tail-lights, glass and even detail things like door handles would not be interchangeable.

Our first suspicion would be a bad earth somewhere on the vehicle. Dashboard faults are very often the result of a poor earth contact and the symptoms you describe are spot on for that very problem. So go around the car and check all the earthing points form the battery to the body of the car.

You could also be dealing with a broken solder in part of the circuit-board that controls the dashboard, too. A good auto electrician will be able to test the circuit for breaks and bad solders and repair them quite cheaply. Ultimately, though, the cost of this repair will be determined by how much of the car has to be disassembled to remove the circuit-board.

It sounds very much like fuel vaporization, which suggests the fuel is getting too hot at some point in the system. If you could get someone to fit a fuel pressure gauge to the car you could monitor the pressure and it if's fuel vaporization as I suspect you should see the pressure drop away when the problem occurs. The source of the problem could be in the fuel tank itself, the lines between the tank and the engine, or in the engine bay. Look for any location where the fuel system comes close to a heat source, such as the exhaust system.