I'm confused here...
When you said it reved up for no real reason, do you mean while you were driving it picked up a few miles per hour by itself?
If so, do you have cruise control?

I doubt it's because you got dust in the engine. The air cleaner will pick that out for the most part.

How many miles are on the car? What mods are done to it? Tell about any other contributing factors you can think of.