I used and rate the power boost spray. Especially on engines with over 50,000 on the clock it will clean up the insides and solves some problems like sticky valves. It is a very intensive engine cleaner and I have know MOT emissions failures to pass after a power boost spray treatment. (Power boost spray is available in our POTN shop see link at the top or click here
http://www.torquecars.com/shop/ - our small commission helps us keep the site running

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