# 3.5 2002 Altima Throttle Chamber replacement = HP Loss due to K&N air filter?



## ALTIMA3.52002 (Nov 2, 2007)

My 03 3.5 Altima has 154,000 miles; engine sounds fine but lost HP under load at 3K rpm. 

This happend before at 118K miles (10months ago); I had the Throttle Chamber (MFG# 1611K-8J10BRE) replaced b/c the flap did not open. At 124K miles 2 of the 3 cats became clogged and needed replaced. 

Now the HP loss is happening again at 154K miles. The dealer claims they can re-program the Throttle Chamber & that could fix the problem. They noticed I had a K&N airfilter and they suggested this could be the cause. I've had the K&N for about a year and have kept it maintained. Has anyone else had this problem? Will replacing K&N with a factory filter fix the problem?
One other symptom, I'm having an increase in oil consumption...at 1000miles b/w oil changes you can hear the vavles rattling at engine start, so I add 1 quart of 5/30 which will fix the rattle until the 3000mile mark.

I'm not 100% sold that K&N is the cause of my clogged Throttle Chamber resulting in HP loss. Even though the dealer has seen this before. There has to be something else...any suggestions?


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## roadkill2_0 (Sep 5, 2007)

did you replace ur header pre-cat??...i know that the 02 till 03 altimas had a header cat problem that would explain ur oil cunsumption problem...i cant tell you anything about the k&n filter theory...because i cant see how that would decrease HP instead of increasing it....well anyway...good luck


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## ALTIMA3.52002 (Nov 2, 2007)

Where is the pre-cat located? Is it after the headers? I'm picking up my car in a few hours from the dealer, I'll bring up your point. thanks!

As for the K&N, I think my K&N is too old & debris must be entering the intake disrupting my Throttle Chamber.


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## ALTIMA3.52002 (Nov 2, 2007)

I figured it out: pre cat is after the intake manifold. To answer your question, yes, I've had the Pre-Cat on Bank 1 Firwall Side replaced 30K miles ago. I'm wonder if Bank 2 is now going bad...I hope not...cats aren't cheap!


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## ALTIMA3.52002 (Nov 2, 2007)

Got the car back, dealer adjusted the throttle but it did not 100% fix the loss of HP @ 3000rpm. Pretty Bummed out. I'm taking the car back to the dealer on Monday to further diagnose. Perhaps Compression. If Compression is compromised...am I screwed?


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## roadkill2_0 (Sep 5, 2007)

compression would make sense, because it ties in with the pre-cat and the oil consumption...the pre-cat is connected to ur headers it's covred by the heat sheild, you wont see it unless you remove the heat shield. hopefully its not the pre-cat, because if it is, and ur burning excess oil it means u have a compression problem...that wouldnt be good because you would have to replace the engine....good luck


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## ALTIMA3.52002 (Nov 2, 2007)

Thanks for info Roadkill2_0. I became tired of anticipating a potential engine meltdown so I traded the 2002 3.5 SE Altima for a 2005 3.5 SE Altima. My old Altima had 154,400 miles on it, this new (to me) one as 30,000. I also bought my wife a 2008 3.5 SE Coup. We're an Altima family! The coup...I highly recomend the coup to anyone who is interested in the Altima!


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