Hello I have a 2012 panamera 50k I have a rough idle cold start when car warms up idles fine I changed coils spark plugs cleaned throttle body and put a new oil engine separator thier is no check engine light on any suggestions before I take it to dealer

 

How rough is it? How much fluctuation are you seeing in the engine speed? A quick vid may be best.

 

When I crank it up it idles good when throttle body closes it start idling rough feels like a misfire not like engine jumping around but not running smooth I added fuel cleaner no change after car warms up it drives fine only thing I think is vacuum leak or oxygen sensor or throttle body I reset it yesterday with the 60 seconds key turn 15 off 5 on still no change

 

temperature thing does makes it sound like a O2 sensor as you suggested, you should get something like a iCarSoft or durmetric to read any codes produced

 

No check engine light on can codes still appear when theirs no check engine

 

if it was the O2, then I believe the check engine light should be lite as it is generally for emissions, but it is possible to get codes without the light coming on.(depending on what it is for)

 

Sounds like a leaky gasket .. throttle or intake ..

 

I don't think OBD-II and later cars look at O2 sensor during cold start (open loop). Most O2 sensors require heat to work, so cars ignore them when they are cold. This means the ECU is relaying purely on its calculated airflow numbers + fuel map at this stage. Rough idle is usually caused because what the ECU sees as airflow (and matches with fuel) isn't reality.

Many of these have been mentioned in this thread, but a few to check that relate specifically to airflow/temp in open loop:

1) Air leak is definitely a likely choice - you can do a smoke or pressure test - since this would easily cause a change in air into the engine compared to the reading
2) Bad EGR - an emissions control device that routes heat back into the intake in a cold car. IF the air is colder than the ECU thinks, it's density would be wrong.
3) Bad MAF reading
4) Intake valve leak/TB issue
5) Coolant temp sensor

You may be able to pick up what is wrong with a Durametric reading numbers, but the challenge is knowing what they should be. Unless something is obviously out of range, the only real option is logical testing of components.

 

You checked and changed the plugs. Were any of the coil packs borderline?

You could also try some CRC, or seafoam fuel system cleaner - and I don't me what you dump in the tank. I'm talking about the stuff you spray through the throttle body to clean the intake system and valves. My idled better after I did this, in addition to running some seafoam through the gas tank. Its worth a shot, just make sure after you pull off the intake plenum split you cover it up so you don't spray anything on the sensors. Also make sure whatever you do to cover it up, is secure and won't get sucked into the throttle body while you're going through the cleaning process!!

 

Don't discount the possiblility of needing new engine mounts!

 

Hello yes it was the motor mounts that was giving me the vibration and also I had to replace two crankshaft sensors on panamera I only did sensors at local shop that deal with Porsches parts and labor ran me 693.00 will do motor mounts soon did anyone ever tried to do motor mounts on a panamera