Hmm, you think thats what it is? Im running pretty rich and no i havent got the car tuned yet because i have 2 exhaust leaks. One where the turbo and downpipe meet and one 2ft after where the exhaust hooks up to a flange. I thought it would be from lacking fuel or something buti dont see how because i have a jwt ecu and afc which im running a bit rich on purpose. Clean spot? Have you seen this before? First time ive seen this happen. Its hard to get tools in there so i havent been able to fix the exhaust leaks......