| Only a couple ways this happens. Flooding, where the carb is putting too much fuel into the engine washing down the cylinders for example. Since you are EFI that is probably not the case but, if you have a Power Commander or, another tuning device they may bw causing it. A corrupted PC map can alter fuel curves causing a rich condition. A defective pot on a DFO might cause a rich condition. Even a corrupted map in the ECU can cause it. If you have a Power Commander or other tuning device, take it out of the circuit and test. If the problem goes away, reinstall the map or swap out the unit. If you still are running rich, the ECU might be bad or, you may have major blow by and very poor rign seal the cylinders will be washed down with fuel and that dillutes the oil. | 
