Replaced all 4 O2 sensors over the last year...then the MAF...then 1 Cat...and now ANOTHER O2 sensor! After questioning the Porsche mechanic as to why this is happening, I am told that Porsche has had a bunch of problems in the winter with the reformulated fuels damaging the O2 sensors. He also states that Mercedes is also having similiar issues with its AMG engines.
Now, this somewhat makes sense since I DID NOT have any troubles this past summer. All troubles have been during the past 2 winters.
He summarizes by telling me I need to OCCASIONALLY gas up using 87 or 89 octane. This would somehow force the engine to "clean" itself and all emission components downstream. Then go back to 92-93 octane for several tanks and continue this throughout the winter and until summer blend gas is back.
Does this make sense? or...am I being led?
The car is a 2000S