Originally Posted by thekurgan
My only guess would be you're running a bit on the rich side? Lots of stop-and-go situations? Short distances when cold? O2 sensors starting to age? I'll put up a photo of mine, done at 22k or so, they didn't look that bad.
What's the cause of the rich running? I've had BPM tune for about three months or so, and I don't think the build up is from that three-month period. If it's rich then how do I rectify it? I also have a BMC air filter.