Engine & running faults

Car losing power when accelerating

Loss of power is either a fuelling, air or protection issue. Live data under load is what separates them rather than guesswork.

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Symptoms drivers describe

Hesitation or a flat spot when you press the accelerator
Power dropping suddenly then returning after a restart
Warning light on, sometimes intermittently
Poor economy and rough running

Possible causes

Turbo or boost control faults
Fuel filter restriction or fuel pump wear
Injector faults
Blocking DPF or catalytic converter
Air leaks and sensor faults
Timing faults on chain-driven engines

What you can do

Note the conditions — cold, hot, uphill, motorway
Mention when the fuel filter was last changed on a diesel
Book a diagnosis rather than replacing parts speculatively

How we check it in the workshop

We record live data on a road test, compare requested against actual boost and fuel pressure, then test the components those readings point to.

Is it safe to keep driving?

Have it checked. Some causes are minor; a failing turbo or blocked exhaust is not.

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Related repairs

How we can help

Engine DiagnosticsEngine faults are usually a chain of events rather than a single broken part. We test fuelling, ignition, air, compression and control signals to find where the chain breaks.Read more Diesel DiagnosticsModern diesels combine high-pressure fuelling, turbocharging, exhaust gas recirculation and after-treatment. When one part of that system drifts, the symptoms usually show up somewhere else.Read more Turbo ReplacementTurbo failure often has an underlying cause. Oil supply, restriction and boost control are checked first — otherwise the new turbo goes the same way as the old one.Read more DPF DiagnosticsA DPF warning is the end of a chain of events, not the start. Finding out why the filter is loading up is the part that saves money.Read more

Engine & running faults

Other symptoms in this group

Car stuck in limp modeLimp mode is a protection strategy, not a fault in itself. The control unit has seen a reading it does not trust and has reduced power to keep things safe.Read more White smoke from the exhaustColour, smell and whether the smoke clears once warm are what separate normal condensation from a coolant or fuelling problem.Read more Blue smoke from the exhaustBlue smoke points at oil reaching the combustion chamber or exhaust. When it appears — start-up, overrun or under boost — narrows the cause.Read more Black smoke from a diesel exhaustBlack smoke is unburnt fuel. On a modern diesel with a DPF it usually also means extra soot heading into the filter.Read more Car cutting out while drivingIntermittent cut-outs are among the most important faults to record properly, because the evidence disappears the moment the engine restarts.Read more Car overheating or temperature gauge risingOverheating is one of the few faults where what you do in the next few minutes decides whether it stays a small repair.Read more

Want this looked at properly?

Send us your registration and describe the symptoms — we will tell you what the next step is.

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