I'm not a K&N fan at all, because I'm an employee of WIX filtration, and our engineers have proven the innefectiveness of the reusable gauze type filters. On many makes of vehicles the K&N oil will contaminate the very sensitive mass air flow sensor. This will cause a decrease in fuel efficiency, a rough idle, and general driveability issues. After all, nobody knows how much or how little oil to put on one of those filters. But since it's a new kit, I'm assuming it came oiled from the factory and is probably just right.
Clean your MAF sensor with some CRC electrical components cleaner.
A Toyota tech once told me not to disconnect the battery cable to clear a CEL, because it resets all the ECM functions for the vehicle...that should give you an idea the caliber of technical skills the K&N hotline people have. What would you expect from a company that prescribes the exact same filter media for use on a worthless beat-up old '72 Ford farm truck as it does for use on your expensive, highly technologically-advanced and precision-tuned late model Toyota engine? K&N likes to talk trash about the 'paper filters' on the market, but look at your OE Toyota air filter and tell me it looks like it's made of paper. It's a specialized, highly-engineered synthetic blend that was application engineered to remove particles of a specific size, and it took years to perfect. Sorry,
I think you made the right choice getting rid of the K&N.