The LTI has issues... The AFM is meh, but was required by GM to reach MPG goals. But the PCV and CCV pressure overflow is real on these motors.
The build up will happen and I agree with Mike, carbon build up will cause issue with cats etc. Using cleaners just brakes it off and flushes it down the line to get caught in something else. #NewCats
Not sold on the oil and gas back pressure and build-up that is happening... this is like 800 miles of build up... that's a lot of blow back for 800 miles. Yes some motors are worse, but GM's system only gets onside of the motor.