all started a few days ago, did an oil pan so i had to pull the dp off the turbo. did the job and snugged everything up tight. pulled the car off the lift and drove the car home, on the way my afr went from 14-15 (under normal driving, no boost) progressively richer to anywhere from 10-12.. if i shut the car off then immediately turn it back on and it goes back to 14.5ish, but eventually goes rich..

i dont understand because under wot it stays 11.4... i've searched and can't really find any situation like mine, i am almost positive i dont have an exhaust leak and the aem wideband/bosch sensor is only about a month and a half old. the sensor is about 8-10 inches upstream of the high flow cat.

any suggestions? vacuum line or possibly a bad gasket on the dp??

 

c'mon all these Super Genious Evo Doctors and nooooo one has a symptom??

 

test the sensor and go from there

 

U can eliminate the gasket idea, any exhaust leak before sensor will cause a lean reading.

 

This. If you are going rich then an air leak is ruled out. Any added air into the system would be causing a lean condition. Either you have a bad sensor, or air flow has been restricted somewhere causing a rich condition. If the weather has changed significantly and warmed up then the warmer air is less dense, also leading to richer AFRs. First test the sensor and go from there. If you didn't fool around with the tune or the injectors then look for a clog in the system somewhere, a bad sensor, or weather conditions caused the problem.

Good luck.