I have installed a K&N stock replacement filter for over 3 years. after cleaning and reoil the filter, car run rough with AC on and the SES come on with thw code P1320 and P0305, 5th cylinder misfire. I reset the SES and replaced with the original stock filter, the car runs fine. change K&N back rough again, any one have a solution? thanks

 

sounds like more of a coincedence than anything. the misfire code is pertaining to your coils. 2ks & early build 2k1 have coils with a fairly high failure rate. you could replace one but eventually another one will go bad. i would recommend based on the codes you pulled, to replace all 6 coils. if the oil from the k&n were causing a problem, then it would most likely throw a maf code. also, if you have the original plugs, then you might want to think about changing them out while the coils are getting replaced.

 

i have heard of probs if you over oil the filter. sloppy is right. sometimes the coils are already bad, and changing filters/plugs just causes them to be done. happened to me. i changed the plugs and the car started mis-firing and ses came-on. changed the coils and is now fine