Hey all, I've noticed on my last few motorway trips that when I am keeping the pedal at a constant throttle the power dips momentarily. There doesn't seem to be a pattern to when it happens and it doesn't happen under acceleration. Nothings been changed recently except the throttle cable was replaced but that was over a month ago and the dips have only seemed to start since the cold weather hit.

It's a 2006 spec c

 

I have a Mazda 6 petrol and at constant speed I used to get a pulsing feeling.
slight up down of revs and it was the airbox lid wasn't clipped down properly. Sucking in air.
worth a look.