projectd18

Not sure if this is the characteristics of Porsche engine, but does anyone with the 3.6L twin turbo engine steering wheel vibrate when at full stop? Not crazy vibration but you can definitely feel it, I just have the spark plugs replaced so definitely not related to that. I have a 2015 cayenne s with only 40k miles.

cbakking

I had vibration on steering wheel at stop light as well but it went away after new spark plugs and coils, I have 2015 Cayenne S as well, it's now silky smooth.
Did you do the spark plug change yourself or Dealer? gap should be 0.028 for our car - correct gap on spark plugs effects how engine runs - I had this issue on my other car, sometimes Dealer or Indy shop doesn't bother to check the gap on spark plugs.

projectd18

Hmm i did it myself with the pregap spark plugs, didn't replace the coils though. Do you think its the coils? Didn't think those need replacements so early

wkearney99

I never trust that pre-gapped plugs will be accurate. In the past I've always manually re-checked them myself immediately before installation. 40k miles does seem early for coils. I've got a '17 GTS, which I believe uses the same block as the S and there's no engine vibration at idle or at speed.

cbakking

Yeah, I agree with not trusting "pre-gapped" plugs - always double check them and 40K it's somewhat early for coils but I just got mine done at same time.

projectd18

seems to be the AC compressor that is causing this issue. The vibration is significantly increased once I turn on the air condition and less when i turn off. Anyone know how big of a job is to replace the AC compressor?

edde

Dunno at all about the difficulty with the compressor but all the peripheral stuff that goes with the job done right is for an experienced wrench. Just my 4.8 cents

Another thought I just had. I have an annoying feedback in my steering wheel that I'm certain is tied to power steering which works flawlessly btw. When I had my car at an indy shop for some other stuff I quizzed him about this and after driving it and messing with it he confidently insisted that this was being caused by failed lower engine mounts.

I've struggled with the explanation for some time but it does seem plausible. I'm almost used to it but think about it every damn time I drive as well.

Dr. G7

Can the gap be adjusted in these plugs? Aren't they center electrode?

mmiller260

Checking you got this fixed? I have the exact same car with the exact same problem, driving me crazy; Thanks!

Malmenator

If the vibration is there before you turn on the AC, but the AC turning on makes it more exaggerated, my first thought is motor mounts. I wouldn't think your AC is failing if it's operating fine (cold, strong, consistent airflow). Swapping mounts seems straightforward just like any other transverse motor layout car. If you're going the DIY route (not sure what year your car is and where it stands with warranty terms), I'd tackle the mounts first before messing with the AC compressor.

mmiller260

Thanks for the reply; 2015 Cayenne S; from my research here, the only thing that has solved this on the 958 was plugs/coils and cleaning throttle body. See my compiled to-do list below though. Many have tried these things to no avail. Plugs and motor mounts next for me.2015 Porsche Cayenne S (V6 tt):
Shaking at Idle (idles at 634 rpm, not in Sport Mode), some white smoke from exhaust; no CEL codes; A/C on and/or turning the wheel (power steering) does make it slightly worse:

• PVC valve / Crankcase ventilator / Air-oil separator and hoses: both valves were shot, replaced both with new OEM, no cracks in attached hoses.
• Plugs: Bosch, all look decent/fresh (May replace, gap to 0.028”)
• Coil packs: ok, all at 389 Ohms w/ multimeter
• Air filters: new/clean
• Air intake, gaskets, hoses: boxes sealed, no cracks visible
• Vacuum systems / hoses: no cracks visible
• Clean throttle body: removed/cleaned twice with TB cleaner (need to reset?)
• Throttle body O-ring (mani side): 4 indent marks in middle, non-sealing edge; May need to replace
• MAF: (not present on ‘15 “S”)
• MAP: cleaned w/ mass air flow sensor cleaner
• Motor mounts: ? (hydraulic filled?), need to locate all
• Gas Cap: no audible “click”; cleaned and flipped o-ring; Buy new Audi Q7 gas cap that “clicks”?
• Oil Cap: cleaned and flipped o-ring; Buy new Audi oil cap gasket?
• Fuel injectors/valves: Dirty from failed PVC’s?? Run Sea Foam thru??
• Idle stabilizer valve (IAC Valve): ?
• Intake manifold gaskets: ?
• Fuel pump and/or fuel tank ventilation purge valve line: (not present on 2015 “S”?)

mmiller260

Oh and thanks for the vid! Perfect timing!