The sound occurs during acceleration in 1st through 3rd gear and the sound gets stronger the harder you press on the gas pedal. I have no CEL codes, the engine has about 44k miles, always used 91 octane gas, and my engine oil is up to level.

What do you guys think this could be?

 

you have a small child trapped inside your engine and he wants to get out.


or the dead hooker in your trunk wasn't as dead as you thought. hit her in the head again and retest.

 

r u stock? if not which mods do u have?

 

ha!

 

if it doesnt occur in 4-6 gears then its most likely a transmission problem and not the engine.

 

Not modded much, just a Nismo cat. Another thing I forgot to mention is that when I hit the gas pedal during low rpms between 1k to 3k is where the sound is noticable.



Also thanks for the comedy relief, much appreciated.

 

lmao never a dull moment reading motormouth's replies

 

but for seriousness:

- where is the sound coming from?

- if the car is not in gear and you rev it, is it still there?

- does it change with RPM?

- did you reuse the cat brace that is on the stock catalytic converters?

- what year car do you have?

 

1- The sound comes from the front bottom of the car and I can hear it evenly from both sides.

2- There is no knocking when the car is not in gear and I rev.

3- The knocking only seems to happen when I accelerate hard and fast it can be heard from 1k through 3.5k rpms. If I accelerate very slowly and softly through the gears, the knocking is not heard, it's only during brisk acceleration.

4- The cat brace is still there and was not touched when my Nismo exhaust was installed.

5- I have a 2004.5

 

ok, I am going to say it might be either a broken or loose end link. when the weight shifts to the rear under accel it alters the pivot of the end link and could make the noise.

or it's your undertray slappin' against something.

..I mean, how loud is it and is it like a metal on metal knock or plastic sounding?

 

Maybe it's actual detonation, that a lot of the 91 octane guys have experienced on otherwise stockish cars. If it's a rocks in a box sound, under load, then it's probably knock.

Sometimes, a simple catch can can help eliminate this minor knock. Oil that is injested through the intake (through your PCV valve) will contribute to knock.

 

It does sound like rocks in a metal box. I will check the intake for signs of oil. Are octane boosters used regularly by 91 octane users in order to prevent detonation?

 

Those little bottles of booster don't do anything. I would try the small catch can.

 

Thanks Sharif, I will be picking up a catch can.

 

Have you tried a different brand of gas or different station location? I sometimes get a knocking sound (regular engine knock), similar to what you listed above, with a cheap/no-name brand of gas.

 

Throw a tank of 89 in it and see if it changes. If its actual detination it will get worse.

 

I have noticed this same problem recently with my 2004.5. anyone have an update to this old thread? Please let me know. thanks1

 

my beater does this bc of all the oil it burns. I run 93 octane and it all goes away.

 

i have same problem as well i have 35ht anvi and i heard knocking sound when i acc on 1k to 3k rpm;;
and i always use sunoco 93 or shell vpower

 

I'm going to get my spark plugs pulled to examine carbon fouling.

In addition, I'm going to check my battery for wear and see if they need to be replaced. Apparently the OP replaced his battery and doesn't hear this noise anymore.... strange


I also noticed a constant, rhythmic noise, sound like a brush scrubbing back and forth near where the electronic throttle control unit is located. Gets faster as I rev the engine.

this is driving me nuts....