Annoying revving sound

Did the car begin to slow down as requested?

If so, you have simply experienced your first emissions purge.

So far (24,562 miles), I have only experienced 2. Both were during the cold season while the system was still warming up. It's part of the design to deal with collected pollutants.

 

<div class='quotetop'>QUOTE(john1701a\";p=\"52100)</div>

O.K. I'll bite.
What is an "emissions purge"?
[The semi-technical version . . . not the "car-fart" version.]

 

An "emissions purge" is when certains pollutants, which cannot be cleansed by just a normal catalytic converter pass, are run back through the engine again to basically cook/destroy them to a more friendly form.

 

I have started to notice this pretty regularly. I live on top of a very long hill and as I come down every morning I noticed this high rev. phenomenon you speak of. Naturally I'm coasting/breaking all the way down and as I get to the bottom of the hill the revving starts. It doesn't last long but it is a consistent problem.

Not knowing much about Catalytic converters, do you think this too is an "emmisions purge." I've got 15k miles on my car.

 

I notice this all the time. when i leave my house i get up to speed very quickly. I used to get up to speed slowly but when the engine is warming up it's seems better to just get up to speed without the wait. It doesn't care to go slow when warming up.

anyways, when i'm leaving the driveway my engine turns on as i turn left onto the street. after i'm done accelerating.. er.. punching it real quick, it will do the rev/"emissions purge"

I'm used to it.

 

is this documented somewhere in the manual?