Roadster Jay

I have an engine vibration that varies in magnitude but always around 3200 RPM. A fellow 991 owner says he's had it in his last 2 cars - both 991.1 Carrera S's. Mine is a stock Carrera and 2 dealers say it's "normal" . At times I would rate the vibration a 7 and at other times a 3. Friends car has active engine mounts and mine are standard, and due to the variation in severity at different times I'm inclined to say it's not mounts. Any data on what it is that causes this?

Needsdecaf

Oh oh.

Look up stutter / shudder. There is a long thread on 6 speed.

991carreradriver

Completely normal. Both my 991's have it at 3250 RPM.

hansw

I haven't noticed this on my '12 991S with 25,000 miles on it.

Needsdecaf

Mine doesn't.

STG

NOT normal.

Most likely the noted "stumble" issue

pfan

I dunno. The stumble tends to hang out @2600 rpm or thereabouts.

Roadster Jay

I haven't been able to locate the stumble / shudder thread you reference in 6 speed ( I'm new to this site), but the condition comes and goes and has absolutely no effect on performance. There is no shudder or stumble in the cars performance. It's simply a disconcerting vibration that sometimes occurs at 3200 RPM. If you command the RPM at idle you can feel it but at times driving, it can be much more pronounced - at other times hardly noticeable. Thanks for the input - other thoughts - additional guidance???

STG

Yeah, you're correct. Seems like not that.

991carreradriver

I have checked this issue out every which way. It appears to be a harmonic imbalance. Not all that uncommon is engines. I have learned over the last three years not to hang out at 3250 and it has become a non issue to me.

This has nothing to do with the hesitation/stumble issue referenced previously.

LexVan

I don't notice this in my car. If it's there, I'm immune to it.

991carreradriver

You will hear (not feel) a metallic vibration sound coming from the right rear engine compartment. It starts at the 3250 and end's at 3350. So as you are going through the gears quickly, you will not hear it as it will be drowned out by engine noises and exhaust. This issue has been around since the 991 was intro'd.

We have had folks do everything to find out the source, no luck. Since no one could find anything vibrating outside the engine (heat shields, clamps etc.) the cause has defaulted to the engine itself. It started on my 2014 at 1600 miles. It started on my 2016 at 8 miles as I drove out of the dealers lot.

Al.Fresco

I had something very similar prior to adding PSE. Noticed it mostly on highway in normal mode when slightly accelerating up a hill... would get that harmonic vibration coming from right rear. Would have to paddle flip back a gear to make it go away. That said, after adding PSE, no more vibration in that situation, and I can be in normal, sport, PSE on or PSE off. Adding PSE itself just seemed to eliminate it.

Roadster Jay

Thanks for all of the input. I am curious why there is such variation in it's presence. PSE ? Could you please clarify for me - unfamiliar with the acronym. Thanks...

991carreradriver

Here is the extensive 6 Speed Thread on the vibration issue

http://www.6speedonline.com/forums/9...-3300-rpm.html