[Joel]

Ok, the problem with these oily filters is that the oil has a tendency to end up fouling your MAF sensor (Mass Air Flow) which screws up fuel delivery precision.

Something else to consider - a less restrictive filter lets more crap into your engine. In my opinion - these aren't worth it.

 

[Joel]

Our experience - regarding after market filters is that they tend to have two draw backs:

1) They are less restrictive so more particulates enter the IC engine's intake.

2) These filters tend to use an oil that can sometimes leak in to the intake tract and foul the MAF (Mass Air Flow) sensor - which will lead to reduced economy and possibly IC engine trouble.

Based on these experiences, we defer to original Toyota engineering.

 

[Joel]

We have several documented warranty cases where MAF fouling was blamed on an oily residue weeped from an after market air filter. I'm glad you haven't had any trouble with these after market filters but obviously some people have.

Ok, the problem with these oily filters is that the oil has a tendency to end up fouling your MAF sensor (Mass Air Flow) which screws up fuel delivery precision.

Something else to consider - a less restrictive filter lets more crap into your engine. In my opinion - these aren't worth it.

This is incorrect. I have used K&N for nearly 15 years, on 3 vehicles without issue. Two have MAF's, no issues. Being an automotive engineer, the MAF's have been inspected for other reasons; no oily residue or other degredation found. Also, the K&N is a more efficient filter that actually traps finer particles than a standard filter. The company and their filters have a long, postive track record. This is a matter of choice, however a filter designed for air flow and efficient filtering performance, which costs more, compared to a filter designed to meet minimum requirements at the lowest cost, is clearly a better choice in my view.