Engine revs 'catching up'
Whilst driving the engine sounds like it is 'catching up' or 'dropping down' without pressing the accelerator
Asked on 14 January 2013 by b266
![](http://images.honestjohn.co.uk/imagecache/file/pad/120x120/media/16477727/537450_458533677529584_1473549666_n.jpg)
Problem with idle control valve or mass airflow sensor or with emissions control device.
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