wolfsburgde

2007 Carrera 2 3.6L M96 with 63,770 miles.

This is probably just me noticing increased vibration at idle since replacing my old and somewhat floppy engine mounts but I figured I'd check for fault codes (none current or pending using Durametric and a generic OBD2 scanner). I graphed the roughness for each cylinder with Durametric and here's a clip from the engine warmed up feeling slight vibration through the seat:


Can anyone shine light on how those numbers look? I don't see a cylinder that's way outside of the others, but 1 tends to be higher most of the time. The engine is totally smooth accelerating part load, full throttle, etc. I have no smoke at startup, exhaust tips don't seem excessively dirty, oil consumption is very moderate. Thanks for any opinions and guidance!

Hella-Buggin'

Here's a Video by Raby on just this topic.

wolfsburgde

Thanks, Hella-Buggin'. I watched that video but it was a while ago. The 996 in his example seemed to hit 1.2 once or twice and he didn't seem concerned til it got to "4 or 5 or 40". Mine seems to be in a similar range to his good example in the vid.

snaphappy

Things that smoothed out my idle: 93 octane gas, air filters, battery disconnect, 5W oil, engine mounts, throttle body. Not necessarily in that order.

voiceprint1

did the throttle body smooth this issue of vibration out of the cabin?

wolfsburgde

Following up on this, changing gas brands made no difference. I haven't tried cleaning the TB yet or inspecting the coils/plugs (much more labor-intensive) but I did look up how to log using Durametric and here's a snapshot from this morning warmed up idling after a drive to work:

I would describe the roughness as similar to the subwoofer bass vibrations, if I turn up the music, the roughness gets lost. I'd say I'm not too concerned with values that peak around 1 or -1 but another set of eyes would be appreciated.

nsau

My idle had gotten really rough at around 60k miles. Replacing the old motor mounts with new stock ones and changing the coils and plugs fixed it.

93Jaffe

My idle is rougher than I imagine OEM should be but I'm at 100k miles (passenger seat has noticeable vibration). I plan to change the engine mounts, clean the TB and air sensor as well as replace the AOS.

I'd bet money new mounts, plugs and a good cleaning is all you need.

Hella-Buggin'

Have you taken it into a mechanic? I wouldn't be driving it around if I knew something wasn't right.

snaphappy

This