rob76turbo

Has 106K miles. replaced plugs / coils about 30K ago. NO CEL.

So at start up, the truck idles very roughly, until you drop it in drive and accelerate. No issues during acceleration / running. But it vibrates again when idling at a stop light. Revving the motor cures the rough idle.

Maybe crank case vent valve? I would think if it was a vacuum leak or secondary air / fuel pump, it would throw a code?

Stumped!!
Thanks,

rob76turbo

I was also thinking it could be motor mounts. The vibration is only in park or in drive at idle. Goes away once under way or by pressing the accelerator

I have done a lot of searches, but nothing seems to match up with what I am experiencing.

thanks again!!

kalyan

Did you figure out what was wrong? I am having similar issue as well.

thanks!

endless_corners

Sticky throttle body could do it. Look through here for a few possibilities. http://www.pelicanparts.com/techarti...yenne_Tech.htm

kjbu

Maybe it's time for replacing timing-chain. The V6 has a design fault in timing-system. Mine was replaced at 130k km.

rob76turbo

Ended up replacing motor mounts and intake gasket (which was leaking badly). That cured it to the tune of $2300. Very tired of spending $$ on this suv.

kalyan

Thanks for your input, rob76turbo. I was thinking the same too. I will check the mounts this weekend.

Endless: I will check the throttle body as well. It is easy to check.

kjbu: Mine is a V8.

Thanks all...

kalyan

Update: It was the engine torque damper/strut. Replaced it last night and engine is smooth and quiet.

PorscheMonster

Wait so engine damper is code word for engine mount?

kalyan

Engine damper is on the top of the engine while the mounts are in the bottom. different things...

deilenberger

Thanks for posting the solution - it makes a thread like this so much more valuable to someone facing the same symptoms..

Edwinner

Hi Rob, I have 2009 V6, with the same symptoms with yours except rough idle.
I am thinking engine mount issue. So did you remember how hard to replace it? Is that possible to DIY?
thanks

Ericson38

I recall in one of these rough running VR6 (DFI like yours) scenarios that it ended up being an injector leaking badly. They had been through the plugs and much more, ending up pulling the engine, getting another...

Bottom line was the original engine was made whole again after the dribbler was isolated and replaced.

Keep an eye on your oil level and smell for gas.

Rob I'm sure has the link to that story.

Shawn Stanford

The times my VR6 has run rough, it was because of a failing coil.

sloanautomatic

Does this video resemble what you guys were experiencing? My 955 cayenne does not accelerate at first attempt. Almost like it is trying to find the gear? But after that first attempt, it seems to accelerate normally. But the grinding rhythm in that video continues for about another ten minutes. I feel it in the small of my back, coming in and out.