Engine vibration

[JE 17]

I bought my 2012 S (yes, it's a 997) about 15 months ago. It has 75,000 miles presently.

It has had a vibration at higher speeds the entire time. I considered a balance problem but went ahead with the purchase of a NVH software program. It confirmed the balance issue and I had them done. They also checked for runout and any other anomalies.

When I got it back, I took a roughly 1000 mile trip, and the vibration was present the entire time. I checked with the NVH program which is now telling me it is an engine balance problem.

The motor and transmission mounts are new OEM. I had changed the plugs and coil packs already. Tires (Michelin) still have good tread.

It starts fine, pulls strongly and uses no oil, but just has that vibration at 70mph and up as well as at idle.

I have an old 986 Boxster which is dead-smooth, so I expected the same of the 997. Is that a characteristic of the new engine?

[Loren]

Any engine fault codes?

[JE 17]

That is what is really annoying: none,

[JFP in PA]

I would start looking at the drive line: wheel bearing hubs, axle shafts, etc. If the engine had a balance problem, it would shake revving it in neutral; if that isn't the case, the drive line is all that is left. 😉

[JE 17]

I will do so.

Just annoyed I had a PPI done. Would you not think it would pick that up if someone was halfway competent?

 

[JFP in PA]

All depends, did the PPI include a full road test of the vehicle?  If it only included a lift inspection, probably not.