Toytoa Corolla Engine Air Filter

Oiled air filters can eventually foul MAF and MAP sensors as vapors from the oil form deposits on the sensors.

Air filters that allow more air to flow that are the same physical size as the OEM filter sometimes allow more particulates to pass through so you will need more frequent oil changes and you may also experience more engine wear.

Some air filters are physically larger so the air filter housing has to be changed out and which take up more room in the engine compartment, making some things harder to service.

In my experience, the negative aspects of aftermarket "high flow" air filter systems outweigh the theoretical performance enhancements unless the car is going to be used in competitive events.

I do not have personal experience with K&N filters; I've just diagnosed the fouled MAF and MAP sensors.

I was wondering if that would muck up an air sensor. I see there is a non oiled after market filter available

I only asked because the K&N version is available locally and I'm due for a replacement filter soon. I guess I'll stick with the original Toyota equipment.