Originally Posted by Vicster

I've had almost the exact same issues. Dealt with it myself for a little while but eventually it threw a CEL so I took it to the dealer. They said it was the K&Ns and that oil from them damaged the MAFs and they would need to be replaced and not under warranty. I decided to just clear the CEL myself, clean the filters and ensure no excess oil, and spray the MAFs with MAF cleaner.

It got better immediately and I didn't have an issue for some time. Eventually though I started to get the feeling of overall decreased performance and recently I've had the codes (not the CEL though) thrown. I've cleaned the MAFs a second time which seems to restore some performance but the reaction is sadly random and not very consistent.

I'm beginning to think that maybe the dealer had one thing correct and that is that the MAFs actually need to be replaced. If this is the case I believe K&N warranties their product under Magnuson Moss and will reimburse you for the replacement of parts not covered under manufacturer warranty "apparently caused" by their filters. Thing is, if replacing the MAFs helps and the cause was the filters/oil I wouldn't want to use them anymore (and for that matter any of the CAIs also utilizing oiled filters, which immediately limits some of my favorites. However Stillen has released a new Gen3 dry using AEM filters.).

The other problem is that some of the issues mentioned relating to the throttle sensor definitely make me wonder if that is the problem. Interestingly, before reading this thread my instincts where telling me that it was primarily throttle response which seems to be the symptom. Hard to say exactly what is the problem so I'm very interested in seeing what your experience turns out like.