engine rev.

out of nowhere the car will rev on rpms but doesnt loose power, and then drop to reg. but i can feel the rev(as well as see it on dial)???

if your describing a high idol speed, i had a very simular problem, i cleaned out my EGR, and Air intake manifold with carb cleaner(about 5 bucks), and what i think really did it, was repacing my PCV valve, it was 2 dollars at canadian tire and i beleave it was the problem,

my high idol hasnt come back in a week