My car starts but fails to accelerate

Hello Paul, my 2005 VW Touareg 3.6 V6 petrol starts and fails to accelerate before the engine stops. What could be the problem? Esther

Hello Esther, a petrol engine start and no acceleration condition or start and stall can be caused by a broken down throttle body or faulty fuel delivery system. The throttle body on your VW Touareg helps to regulate inflow of air which determines the air-fuel ratio when you accelerate. A throttle body may break down overtime due to buildup of grime, dirt or soot especially after not regularly maintaining your air cleaner.

Occasionally, it can suffer vacuum leaks or electrical failure of the throttle position sensor. A computer diagnosis will help to investigate that possibility. A faulty throttle body will cause poor or no acceleration, unstable idling or stalling.

A broken down fuel system is usually due to failure of the fuel pump. It is common for gasoline or petrol vehicles such as yours to suffer from fuel pump failure due to a delay in renewing the fitted fuel filter.

As a result, the filter gets clogged with dirt or grime and allows dirt to flow through or restricts fuel supply. This may restrict fuel pump performance or damage it.