Hey all...
My car started making an odd noise a few weeks back, It started about two weeks after I changed all of my belts....it would happen after the car was warmed up, and was especially noticeable at idle when coming to a stop after a long (5 mins.) cruise... once you got over 2k rpm the noise would go away...I just figured maybe I put one of the belts on poorly or maybe had a bad alternator bearing or something....
So finally today I got around to looking for the cause...drove around to warm up the car and there it was....I started walking around the car trying to locate the noise...finally I put my hand over the snorkel on my air cleaner and I could change the pitch of the noise (kinda of a moan....can't wait to hear the jokes on that )...anyway took the top off the air cleaner and it was pretty loud....really doesn't sound normal (another way to describe it would be an off key constant trumpet noise).

Does anyone have any ideas why it would just present itself now? Any ways to correct it?

I should mention, no real performance issues...my car has always had a slight stumble just off idle, but other than that it starts and runs exceptional.

 

Are all of the hoses that run to the air cleaner still hooked up? Stock, I believe there are 5 hoses that connect to the air cleaner. 4 are rubber, and one goes to the exhaust manifold heat shield. Anywho, things sound much differently when they are not being fed 'restricted', but clean, air from the air filter. Oh, and check this out too...it may be your problem as well:

http://mazdatrix.com/faq/shutter.htm

good luck!

 

Thanks Dankekong!

Put my finger over the hole...wella! No noise! Any yes there is a vacuum there.

So...how important is the shutter valve....gonna start my search'n right now.

 

Mine is hooked up but i have the vacuum capped as i removed my emissions when i rebuilt the carb. Honestly, not that important obviously lol. I have another link that will help greatly if you want to cut down on ur emissions....at first i didnt, but it really cleans up the engine bay and unrestricts the car a touch