Just took a drive today, and i can feel the gear shifter vibrating diferently passing 2900rpm and when passing 3100rpm the vibration is gone. Although bring it back to idle or anything below 2500rpm the same original vibration comes into play, that is more like rough running.

 

Well locally there is a 968 owner that had a mystery vibe problem in his 968. Never seemed to figure it out. That was a few years ago so maybe he resoloved it.

You may want to contact him.

Name is Dick Petticrew and his is the safety chair for our local PCA. Contac info is here.
http://az.pca.org/contact.htm

 

Something that causes issues in the newer cars along this line is the Dual Mass Flywheel, I have seen first hand the two elements seperate and cause EXCESSIVE vibration.

Mark

 

Well teh Flywheel was one of the probs i thought, but i replaced the DMF and the whole Clutch.and still it shakes. Im gonna try re index the cams agains, and triple check that everything is dead on.
Since teh DME doesnt show any codes. Im thinking maybe the prob could be fuel pressure? Too low? Too High?

 

Did you check for any vacuum leaks? They can cause rough idle.

 

Also replaced all the small vacuum hoses i could find. And vacumm reads normal 18 to 19 hg at idle (hot) and beahaves within norm revving.
Also the Injectors were cleaned, although they are a bit loud lately, almost fooled me thinking they were lifters, but these were changed too.
pLEASE keep the ideas coming.