Iridium Spare plugs degradation.

[german]

Folks,
Some one knows what is the Iridium s/plugs life?

after 20,000kms with the Iridium S/P i feel slow the Eng reaction like air/fuel mixture rich, phisically have a bit of erosion.

Now my cat has 53,000km

Thanks for your comments.

BR

[JetdocX]

Does the fuel contain lead?

[german]

no lead,

[JetdocX]

Remove and inspect.  I replace my plugs every 6000 mile service, YMMV.