Unequaledone

my s4 seems to shake (not vibrate) more than what seems normal on idle; has been doing so since day 1, now has 5k and still does it. Does anyone know what is used or how to check the idle quality on a car?--I read once in HotRod that they do that, but forgot how.

Taner Halicioglu

use a vag-com... it will show you all the misfires (and which cylinders)

Unequaledone

I had the dealer check for error codes--there were none; they checked all the mounts (engine, trnas., exhaust, etc...), they say that "there is nothing wrong with the car,' but it is pretty bothersome. Do you think that if I prove to them that it shakes more than all the cars on their lot they will do something about it?

Taner Halicioglu

especially if you have only 91 octane gas... (ie, you live in California).

Not sure where you live tho.

But if you use teh vag-com to watch the misfires, you can see if you are getting an excessive amount or not.

007 S4

My car burbles a bit at idle. Is that misfiring? I mean.. I'm Using 93 octane (R+A/2) fuel. Maybe I should fill'er up with a tank of 100 octane race blend.

Any suggestions? 93 or 94 octane with octane boost or something? Fuel injector cleaner?

dvsadversary

I use 93 octane and it still shakes, extremely annoying

M3EATR

From what I've read on this site and my experience seem to show that the S4 just idles rough. If you push on the gas a bit and have it go up 500rpm or so, I bet the roughness goes away. I'm not sure, but I think it may have to do with the "Tumble Duct" cylinder head. That sort of design will need a bit of airflow to start working properly. At low airflow, the flow patterns aren't established and I can see there being rough idle. I hear that this type of cylinder head was benefictial because of the high compression ratio on this turbo charged engine. This may or may not help you, just an FYI...