Flapping sound when over 5K RPMs
 

My car just started to make what sounds like a flapping sound whenever im running over 5K RPMs. It sees to be coming from the drivers side. I cant tell if its coming from inside near the steering/column area, or outsides in the engine bay behind the steering area.

What could it be?

Also, I just had my engine oil, transmission oil, gear oil, clutch fluid, and an alignment done, if that matters...

could be the under tray that was left loose

I dont know cause it sounds like its coming from the upper area, like under the steering wheel near column.
I guess ima have to take it back so they can check if the did leave something loose.
Its like a loud flapping/clicking sound.
Ill try to record it tomorrow and upload it here.
I wont be able to take my car back until Monday because of work.

Get under the car and look for loose stuff, most likely its the undertray, techs usually put it o. Like 3 screws out of 15, cuz they r lazy. So u underpayed a guy(am guessing), this is the result.

I had it done at the dealership actually. I dont trust other small shops, bad experience.

anyone else had a similar issue? maybe it is something mechanical?

Is it actually rpm related, or speed related? Try getting it to flap, then up-shift but stay at the same speed. I'm guessing it's speed related, and you've got a loose plastic undertray (like stated above). Mechanical noises are usually whines, grinds, knocks, squeals, etc... not flaps.

It is definitely RPM related. Ive tried checking in gears 1, 2, and 3 and then up shifting, etc.. and it always happens when over 5K RPM. I could be going 80mph in 6th gear and no noise.
I guess It could be described as a knock?
Like I said earlier, I feel its coming from the steering column area, or just right behind the actual steering wheel or gauges. Hard to tell where noises in cabin come from sometimes.

Even if its not speed related, maybe there is something loose and it doesnt occur until higher engine vibrations at higher RPMs... but I guess I wont know till I bring the car back in.

That's a little more worrying then. Are you noticing any other vibrations besides the knocking/flapping noise? It's gotta be something loose that a specific harmonic at 5k is setting in motion.

Was the intake manifold cover (plastic thing on top of the engine) removed and put back recently? That would do it, if it was loose... And it's probably insulated enough from wind that speed wouldn't matter, but rpm definitely would because it's bolted directly to the engine.

I tried checking the engine bay for anything loose or left in there, but couldnt find anything. Ill try checking again.
I really hope its nothing serious! :(

I'm an idiot for not thinking of this sooner... If it happens while not moving, get someone to rev your car to 5k while you stand to the SIDE (safety first) of the open engine bay and see if you can find what's wrong. Sometimes it's hard to isolate an engine bay noise from the wrong side of the firewall.

Ill try this, but im pretty sure the rev limiter stops at 5K when in neutral.

I had the same issue. 09 model also. Almost like a metal flapping noise coming from behind the steering column. Weird thing was that it went away on its own after a few months. I think after I did a basic oil change.

after 5k RPM there's typically a fapping sound in my 09 Z too.......