With both of your post O2 sensors showing 0.7v I suspect you are running slightly rich.
Your sensors are faulty.
Or your Cats are faulty.
That's why I asked about the air filter.
Dirty air filters restrict air flow and after market filters that use oil on them ruin MAF sensors.
Does your scanner show live data?
If it does hook it up.
get the car fully warmed up and at idle look at your pre Cat voltage signals.
They should switch above and below .450v every few seconds.
If they stay high constantly that indicates a rich condition.
Here is a test to try. If you have live data.
Hook up your scanner so you can watch your O2 sensor voltages.
Get the car fully warmed up.
Then create a good size vacuum leak. This will create a lean condition.
Voltages on the O2 sensors should drop down close to 0.2v
Pre Cat sensors should see the lean condition very quickly.
Post Cat sensors will take a few seconds to see the lean condition because they are behind the Cats.
If they don't or they respond slowly the sensors probably need replaced.
Or in the post Cat case the Cats could be faulty.
I hope this all makes sense.
Also there may be some issue with your Evap. system.
But I am not up on Porsche Evap systems so I would be of no help there.
Last edited by blue62; 08-10-2020 at 11:30 AM.
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