Coming up to my MOT and due to short journeys in my diesel I decided to do a motorway run. I noticed slight loss of power in 4th and 5th where the car shakes slightly.

I am thinking it maybe a buildup of particles crap due to my short journeys, even though I have had my dpl filter removed. Or it maybe a stuck egr valve.

My EGR spray says to spray it in the Air Intake Manifold. Can on the pic provided tell me where the manifold is. (please ignore the circle)