There have been some updates to the air intake system. If you have them, check the seals in all of the areas where the air comes in. The pre-cleaner connection on the exhaust and the valve in the exhaust pipe are another area to check. Our experience is that if you have any inlet problems that it fills the pre-cleaner centrifuge area where the dirt is supposed to be spun out. If this is plugged with dirt it cannot work so if you have any inlet problems and get them fixed, you must then clean out the centrifuge area. That took care of it for us.