The K&Ns are oiled filters. Even when its new it has oil on it.
If your hilux is going into limp mode that often, you should clean the MAF sensor. Be very careful when you're cleaning it as it is fragile.
Also, I'd recommend when you clean and reoil the K&N, do not apply excessive oil, and let it sit for a day before you reinstall it in the truck. I had a spare original toyota paper filter that I would use while the K&N is sitting after being oiled.
I agree with Big Z, do not wash the filter too often. I cleaned and reoiled my filter ( and MAF Sensor) every other oil change.
Hope this helps.