Car Losing Power?
Find Out What’s Wrong

The diesel particulate filter traps soot from the exhaust. On vehicles used mainly for short journeys the filter never gets hot enough to burn off the soot — eventually blocking completely. A blocked DPF triggers a warning light and puts the engine into limp mode with significantly reduced power. A motorway run at sustained revs can clear early blockages. Severe blockages require professional forced regeneration or replacement.

On turbocharged engines a failing turbo or split boost hose causes immediate and dramatic power loss. The engine feels flat above certain revs where the turbo should be providing boost. A split intercooler hose is the most common and cheapest cause — often detectable as a hissing sound under acceleration. Turbo bearing failure causes a whistling noise and oil smoke.

A partially blocked catalytic converter restricts exhaust flow — creating back pressure that reduces engine breathing and causes power loss particularly at higher revs. The symptom is often worse when the car is hot. A blocked cat is typically the consequence of another fault — misfires, oil burning or rich running — so the underlying cause must also be identified.

The EGR valve recirculates exhaust gas into the intake. When it sticks open it dilutes the intake charge excessively — reducing power output particularly from low revs. More common on diesel engines with high mileage and frequent short journeys. An engine management light is usually present.

A weak fuel pump or blocked fuel filter starves the engine of fuel under load — causing power loss particularly during hard acceleration or at higher speeds. The symptom may only appear intermittently at first before becoming permanent as the pump deteriorates further.