funny sound at 3800RPM (sounds like vtec)

i just filled up petty, and just gave it a hit, and realised that around 3800RPM, the car made this wierd sound for about 200RPM, until 4000RPM. it kinda sounded like metal vibrating when i first heard it, and like it was coming from driver sound, around the intake

i have the stock intake pipe arm, only a K&N panel filter, so i dunno how the sound can be coming from my intake

after trying to hear it a few more times, and hitting vtec after, the sound is similar.

so it sounds like, vtec for 2 seconds, but more, tinny?, when i rev to 3800, then when i get to 4000 the sound goes away, then around 5500 vtec kicks in, like it usually does

ive had the car for a year now, and this has only just happened 2nite, i'll check if its still happening 2morrow but yeah

anyone have a clue what it mite be? ( i popped the bonnet and everything looked fine .. though it was dark, but everything is bolted on sturdy, as i thought it mite be something loose)

btw the car is a bb6 vtir auto, and it only noticeable in gear 1 and 2, gear 3 is less, gear 4, no sound other then the usual

and driving normally is fine, nothing out of the ordinary

spun bearing?

does the noise increase when you step on the pedal?


edit:

then you can scratch of spun bearing,

so it lasts 2seconds

what u mean? like if i press on it harder, it makes the sound increase for that 2s?

if so, i didn't really notice, you can only hear it if my foots all the way down. i can't remember how it sounded without my foot all the way down, but i know there still was the sound

and its not like a knocking sound

it sounds like you filled up the wrong petrol, and your car is pinging upon load.

you put too much pressure on teh accelerator, it will sound liek that as your motor is struggling in the current gear, until the auto transmission selects the right gear, the sound will go away then.

i filled up with v power, and did as well for last 2 weeks
BUT, my dad took my car on a saturday to work, and filled up mobil 3000? the red handle.

as thats not premium unleaded? and my car needs premium? so yeah maybe thats y?

but it doesn't feel like its struggling, the power and everything is still there, just there is a sound

Quote:

---

Originally Posted by MWAKU

i filled up with v power, and did as well for last 2 weeks
BUT, my dad took my car on a saturday to work, and filled up mobil 3000? the red handle.

as thats not premium unleaded? and my car needs premium? so yeah maybe thats y?

but it doesn't feel like its struggling, the power and everything is still there, just there is a sound

---

Your car needs premium. Your dad filled in 91 RON... Don't use vtec. Drive sedately and then top up with more vpower.

yea i hit vtec a few times tho when driving with that 91ron, ONLY, to feel why it was so shit

cause there was really bad response (to him it was good, lol -_-), so i vtec'd it, and it took forever.

and i only drove with that for 20L? so yeah, basically i filled up with vpower, then dad filled up 20L of that mobil unleaded, now last nite i full tanked up on vpower

Could be far-fetch but do you have an audio device connected to your stereo/head unit through a 3.5mm aux jack that might have came off loose?

i rkn loose input bearing....cuz mines like that 2. not gunna affect the car.

check if anything is vibrating

Quote:

---

Originally Posted by neo_phase

Could be far-fetch but do you have an audio device connected to your stereo/head unit through a 3.5mm aux jack that might have came off loose?

---

funny you should say that, as i was dangling a few chords here and there trying to get my usb out of this gap thing, so it could be? but then again, i just drove it now, and the car isn't as bad as last nite?

i can't hear the sound nemore driving it slowly through to 4k rpm

but, planting my foot i can still hear it, only slightly, but thats cause im really trying to hear it,

Quote:

---

Originally Posted by Benson

check if anything is vibrating

---

yeah i was thinking that too, because i pushed my head rest (passneger side) down properly as it came up, and after that i tried to see if there was still sound, so i dunno if it was the cause but yeah,

main thing is that the sound is pretty much gone, hehe, thanks for all the help guys.. im assuming it was the petrol thing

loose exhaust bolt