Sasha Jordache

Good day.
I just did gundo hack on my 2009 911 Carrera 4S and after the work done to my car, now i can feel a slight rough idling. is this normal or did they miss something .
thanks :-)

JCD911S

Check that O2 sensors are screwed back in properly, and if they disconnected them from the plug, check that those are fully plugged in and that the pre and post cat sensors aren't switched around.

ltcjmramos

I had/have similar with the SW center muffler delete. In my case, it's only minor, and I do not at all find it annoying.

Matt(inMA)

The mufflers themselves cant cause this. What might is if they were not reinstalled properly - such as a loose / missing bolt etc. I suspect it's not a idling thing as much as a vibration thing.

Matt

JHuggans

First, try cleaning your throttle body. There is a gap between the butterfly valve and wall that collects oil and dirt over time. Get the top and bottom.

Second, perform a throttle recalibration.
Turn key to on position (not start) for
60 seconds
Off
05 seconds
On position
15 seconds

bloomjbmw

I have SW bypass and Fister mufflers on my 997.2 S. Not sure when it appeared but I have a 640-670 rpm idle, confirmed by my Durametric.

Recently, when I noticed the phenomenon, I tried retraining and then replacing my TB. In each case the results were identical. Perhaps the exhaust mod did it. It’s been on the car a few years but I don’t drive it often enough to determine when it started - or - if it’s always been that way.