Unsettling intake noise (AEM)
 

Since the installation of my AEM CAI a few weeks ago I have noticed some strange noise.

When at WOT in 2nd and 3rd gear above the 7k range there is a strange noise. It sounds like the air flow is being disturbed somehow. (It almost sounds like mild piston slap on a car with a reciprocating piston motor but no metal on metal sounds.) This occurs probably 98% of the time. There does not seem to be any power loss whatsoever (no jerking, no anemic feel, etc.), if there is it's so minimal I can't detect it. I have done the following to try and diagnose the issue:

Checked, and rechecked to make sure the VFAD port behind the TB is capped.
Made sure all vacuum lines are secured to the intake pipe.
Checked screens for damage AND placement. I've even reinstalled the pipe twice.
Checked to make sure the tubing leading to the TB coupler is not askew.
Cleaned MAF.
Checked and rechecked MAF seal/gasket.
Reset ECU (on several occasions).
Checked for cel codes (none other than TPMS codes).
Secured piping.
Removed water resistant sock over cone filter.
Checked cone filter for damage.

Any more ideas fellas?

Good question. Does it do it in neutral? If it does make a video if you can. Or just make a video period.

No, Not neutral or first. I planned on it, I just dont think an iphone will get it. I need to source a video camera.

subscribing to see how this one turns out.

I checked the vacuum as a means to check the compression (poor kid style). The gauge was pegged at 17, and was so stable it made Christopher Reeve look like Michael J. Fox.

Next step is an old fashioned seafoam treatment.

Also: I tried getting the iPhone to pick up the sound from in the cab, no such luck so far. I'm going to try a few other things... like duct tape.

scribed. also happening to my 04 AT at 7k rpms. my AFR shows running ultra lean at this point. talkin 11-12.

11-12 really isnt that lean

Issue Resolution
 

A little background on the car may be in order as I describe the solution to the problem:
After the transaction to get the car was finally complete when I purchased the vehicle from the couple that owned it before me, they handed me a set of spark plugs in a white box. They told me that they came with the car, and when the car had originally went in for it's first service, they used plugs they had on-hand to replace the ones from the factory instead of the "extra" set that came with the vehicle. Apparently, Mazda recommends changing the first set out after only a short period of time, and thus why they include an extra set with the vehicle.

"Cool, that's an extra $85 saved when I swap plugs next."

Fast forward a few months, and I did the one thing that people tell you never to do: I installed two bolt-on modifications at the same time... which makes it significantly more difficult to discover what the issue is.

Of the modifications installed, I installed an AEM CAI and the BHR ignition... Which I opted out of extra spark plugs because I had the wonderful factory set.

I swelled with pride, and instead of buying new plugs, I ate a steak and probably went to a strip club. (insert swelling joke here)

From the beginning, I had issues, but they were slight. The issues listed above are exactly what I was having. I was UNSURE of any loss of power, because of the noise that was occurring. I wasn't sure if I was experiencing any, or if it was in my head... However I knew in certain places in certain gears it did not sound like my fallen black rx8. It sounded choppy, unhealthy, and downright scary at times. It's severity would vary from pull to pull, but it was always there.

I immediately re-tightened my plugs, double checked all connections and ground having to deal with the ignition. Nothing.

Then I switched my focus to the intake.

After over a year of hunting vacuum leaks, cracks, dissembling and reassembling the intake at least 6 times, I gave up. Always testing the vacuum with the brake bleeder, and always stationary, never wavering, from 17.

I was safe, but nervous.

I kept tedious routine maintenance, blew out carbon with a redline a day, seafoamed once every six months... Nothing.

Knowing that you've done something to your vehicle to hinder it's ability to perform and not knowing what is wrong or how to fix it can be absolutely maddening. The anxiety will make you sick.

Over the past few months, I picked up on a few things and one was a dead giveaway...

I noticed unstable idle at times and some obvious missing when idle or parked.

So, last week I ordered new plugs from CRH, king of the Butchers, Hacks, and Retards, a company that has saved my ass more times than I can count on several different occasions.

After replacing the plugs this afternoon, I got in the car and started it up.

There was that smooth idle. :cool:

So I cleaned up the driveway, cleaned my tools, and put everything away while I let the car warm up to running temperature. Shut it down, and came inside to take a shower.

A little while later, I hop back in the vehicle to go bash some hot dogs at a Memorial Day cookout. On the open road, I decide it's time to blow the carbon out for the day.

Gear 1, 9k.
Gear 2, No noise from 7 to 9k.
Gear 3, no noise from 7 to 9k.

... Surely not.

I tested again.
And again.
and again.

I could not replicate the sound. Not even once.

I also noticed the car's response is quicker, and the midpipe is quite a bit more active.

So now, I have come home in the evening hours to enjoy some spaghetti and snag my AP to reset my ECU.

It's time to get acquainted with the car I should have had over a year ago.

Thanks to everyone who chimed in with help.

Not sure if OP is even active anymore but I have a similar problem. When I go WOT at 7k rpm and above I get a clattering noise like a piece of paper being flicked repetitively. Its quite noticeable. However if I smoothly go through the revs to 9k rpm, it doesn't happen.

I just changed my spark plugs about 5k miles beforehand when I got my BHR kit at the same time.

Anyone else got any ideas?

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