* Massive Fuel Leak: This is the most dangerous possibility. A large hole in a fuel line, a severely damaged fuel tank, or a loose fuel cap could all cause rapid fuel loss. This is an immediate safety hazard and requires professional attention immediately. Do not drive the vehicle.
* Fuel Pump Failure (less likely but still serious): A malfunctioning fuel pump could be spraying fuel out somewhere, but this is less likely to cause such a rapid depletion.
* Extremely Faulty Fuel Injector(s): While unlikely to cause such a drastic drop in one hour, multiple severely malfunctioning injectors could contribute to excessive fuel consumption, but it's more likely you'd notice other symptoms like poor performance or excessive smoke.
What to do:
1. Do NOT drive the vehicle. A major fuel leak poses a significant fire risk.
2. Turn the vehicle off immediately.
3. Have the vehicle towed to a qualified mechanic. Explain the problem clearly. This is an emergency situation.
4. Do not attempt to repair this yourself. Fuel system repairs are best left to professionals due to the fire hazard.
The speed at which you're losing fuel points to a major mechanical failure that needs immediate professional attention. Ignoring this could result in a dangerous situation.
