K&N filter problem.

I recently bought a factory replacement K&N filter for my 2001 Blazer ZR-2. Even after resetting the computer, I'm getting a Service Engine Soon light. AutoZone said that the code read as a Secondary Air Injection Malfunction (P410 or P420, can't remember which one). I started loosing a lot of MPG, so I unplugged the battery again, and tried another drive cycle. The code came back again. I called K&N, they pretty much told me to put the stock filter back in the truck. I'm just wondering if anyone else has had this problem and found a solution. I really would like to keep this expensive filter.

Search the forum and look here http://www.automotiveforums.com/vbulletin/showthread.php?t=492974&highlight=air+injection

It should have nothing to do with your K&N filter

What engine and trans and mileage?
Was anything else done at the time you replaced air filter?
Was it running good before you replaced air filter?
Have you got all sensors hooked back up good?
Any Plugs fuel filter tune up other work done at the same time?
Drop in air filter or cold air intake K&N?
Lot of difference in a code 410 or 420 post back which one.
The main problem with a K&N filter is the oil. If the filter is over oiled the K&N oil may/can get in the mass air flow sensor and throw you fuel mix off that could lead to a code 420.
Either clean the K&N filter and try it with no oil or put a stock filter back in it.
But either way you will need to clean the mass air flow sensor good with maf sensor cleaner or good electrical contact cleaner.
CRC now has a good MAF sensor cleaner in spray can.
Clean and let dry and hit it again for good measure.
Clear codes and drive it and see what it does.
MT

scholzee hit the nail on the head. Secondary air pump was a problem on a number of year blazers, follow the link and it will tell you how to correct the problem. Good luck

I finally fixed the problem, turns out it was a P0410 SES, thanks to the responses to the forum thread. Turns out that the A.I.R. (smog) pump was indeed filled with water. It is now drained and I spent $2 on a new 30Amp fuse. I also re-routed the intake hose for the pump from behind the radiator so that it doesn't suck in water. My fuel milage has picked back up, and all is well. I even told the dealer that I fixed it for $2 and 2 hours vs. their $400 estimate for the repair. I think the smog pump is one of the easiest accessable parts on the damn truck.

Good job and thanks for posting the solution to fixing the problem, too many threads are left without a conclusion leaving many to wonder how it was resolved.

I finally fixed the problem, turns out it was a P0410 SES, thanks to the responses to the forum thread. Turns out that the A.I.R. (smog) pump was indeed filled with water. It is now drained and I spent $2 on a new 30Amp fuse. I also re-routed the intake hose for the pump from behind the radiator so that it doesn't suck in water. My fuel milage has picked back up, and all is well. I even told the dealer that I fixed it for $2 and 2 hours vs. their $400 estimate for the repair. I think the smog pump is one of the easiest accessable parts on the damn truck.

10-4 on posting back and letting us know how it went.
Thanks MT