Clean the EGR Valve by Hand Once you've let your EGR valve soak in cleaner overnight (if possible) you need to clean its passages, openings. and surfaces with a small brush. Toothbrushes and pipe cleaners soaked in carb cleaner work great. When cleaning by hand, be sure to use chemical-resistant gloves and eye protection.
What happens when an EGR valve sticks?
A faulty EGR valve can cause problems with the flow and operation of the EGR system leading to performance issues including a reduction in power, reduced acceleration and decreased fuel efficiency. EGR valves can become stuck 'open' or 'closed' due to a build-up of soot particles, carbon deposits and dirt from fuel.
Why would an EGR valve be stuck open?
The most common problem with an EGR valve is when carbon build up on the valve cause it to stick (see the photo below). In worst cases, an EGR valve and the EGR passages can be completely clogged up. Symptoms of an EGR valve that is stuck open include rough unstable idle and stalling.