Well as many others here have fought the infamous P0172 code. The other day I was cleaning out the car and figured I'd take my K&N air filter out and wash it. When it was dry instead of recoating it, I re-inserted it and guess what the P0172 (restricted performance) issue went away.

I guess for some reason the Jags don't like the coating on the re-usable filters. Anyway it works great now.

 

Might want to clean the MAF too. Just for prevention.
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I just use a paper filer on the STR. I'm fine with oiled filers on my carbureted Jag. On the STR I stopped using fuel additives (Techron) too.

 

Meant filters..

 

Hi oldtvman,

The question this raises for me is this: will the K&N filter work properly without the oil treatment? A filter that, compared to the stock paper filter, can allow more air (and grit) with the oil coating must be able to allow even more air, but even larger grit, into your engine...

And tbird6's suggestion is well-taken. One of the long-running criticisms of oiled filters is the potential for the oil to contaminate the hot wire in the MAF. K&N firmly denies there are any proven cases of this happening, but given how a MAF works, it wouldn't take much contamination to affect its output signal.

Cheers,

Don

 

I see possible coincidence here. if you had a restricted performance code from a contaminated maf simply removing and replacing the air filter oil or no oil wouldn't cure it, you'd have to successfully clean the maf aswell

 

Actually the issue doesn't surprise me, I have a 2003 Audi allroad that used to have a K&N filter in........yup it threw some codes and a couple times even caused the check engine light to come on. remove and replace with standard paper filter, no more issues. that was about 70K miles ago..........

I have one in my old nissan frontier too, no issues with it, haven't decided if going to try one in the A6 or STR though. They are also rumored to cause issues in certain British marque motorbikes, but I used a BMC with no issues there...........

 

Yes K&N have always denied this was a problem but we need to be aware that the oiling is done by the car owner and K&N have no control over how it's done.

So yes a properly oiled K&N should cause no problems but if you have ever oiled a filter you know it's an not exact procedure. There is no "full" line to let you know it's oiled properly.
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K & N is selling bling. The actual performance benefits are small. We tried them on our motor yacht. They were dumped in the trash 6 months later. I'll stick with normal on this issue.