rev up at startup happens to me about 1 in 10 cold startups. Freaked me out at first but now I see its common so its all good.

 

Hi guys
My first post on the TT board (I think ) but long time lurker.

I just had the high rev problem solved and explained to me:

Throttle body needs to be cleaned regularly; if not, what can happen is the
throttle body butterfly may not close all the way when you last turn your engine off;

what happens then is, upon starting the engine cold, the computer senses a butterfly
that is not fully closed, and revs the engine once or twice attempting to reset it, (close it).

After cleaning mine, it never reved up again at start up.
Sorry if I made it sound confusing.

Same thing, be it a C4S or a TT.

PS I no longer use ethanol; I only use Shell 91 here in Canada

EDIT: Time it took my mechanic to take out throttle body, clean it (very shiny now)
and re-install: 12 minutes.

EDIT 2: it looked very easy and simple to do; next time I am cleaning the throttle body myself.

John