I noticed it today when i would take off in first gear and bring the rpm's up to about 3k or so and let off there seems to be a slight metal to metal rattle coming from the engine compartment through the firewall.I hope it isn't what i think it is...(precatt) and that its just a heat shield or something,car drives fine and no cel.Ill try to get under it this week and check tightness of everything i guess.Anyone ever have something like this ?

 

Could be just carbon build up, try running 94 octane you probably won't notice the rattle sound (seafoam in your next tank of gas will also help clean up any carbon build up)

 

Well i always use 93 at every fill up and i usually rev it out quite a bit so i doubt theres too much carbon in there lol,my usual shift is from 45 to 7k so that rules that out but it really does sound like a heat shield's loose or something.

 

By all means check the normal suspect items, but you would still be very surprised just how much carbon can still get built up ... hope its just a heat shield like you suspect.

 

me too man thanks.

Well i dont no what is causing that rattle but i had a mechanic at work today pry on every heat sheild under the car while i kept revving it and no luck but the good news is he said its coming from the firewall area and he thinks its the precat.The exhaust has gotten a little louder but i just put a cattman catback and a test pipe on it so i cant tell if the exhaust is just breaking in and getting louder ? It sounds just like a heat shield only on a decel like a can with a bunch of change in it shaking around is the best way to describe it and i got no cel at all.This car is making me

 

That's not good news. You need to gut your cats asap.

 

well im thinkin about pulling the trigger on a used turbo kit which comes with them already but if i don't go that route and you have to take them off to gut them i should probably just get some obx's or something.Would you say i shouldn't drive it ? I saw the thread about precatts breaking apart and destroying rings and such.I mean unless its some shield i couldn't see or something.the cars only got 66k on it do some precatts usually fail this early ?

 

I had this problem but only when the AC is on

 

precat. Also put in park rev and let it idle a few times. You will hear it

 

yep. my precats are gone too at 130k miles... this is something severely overlooked by nissan c. 2002-2005.

 

Mine failed at 75k. If you have another car to drive, I would go that route just to be safe.

 

Wtf i think it is the rear bank precatt, im at 67k now even my mechanic couldn't belive it.I need someone to take them off and gut them i guess.The car is my dd for now and was planning on buying a used turbo kit of another org member on here in the next two or three weeks which has headers already with the kit so i should probably gut these asap,they other weird thing i dont get is if you fart to close to a nissan precatt it craps a p430 and i havn't got one yet I was in the car revving it while the tech took a prybar to all the heat sheilds and they all seem fine.

How hard is it to gut them i just need a temp fix ?

 

The most difficult part will be breaking the bolts loose without annihilating the bolt heads.

On a scale of 1-10, 1 being a K&N filter change, 10 being a cam swap with the engine in the car, I'd say between a 3 and 4.

Take your time, use plenty of PBLaster, and be patient.

 

^^^Thanks man

 

I like that scale!

Ive been reading about more and more precat issues lately. Guess I can talk my girl friend into some mods to save her VQ35.

 

Please keep us up to date on what you do and if the sound goes away.

I've had a rattle since I bought my 5.5 about a month ago. Only hear it around 2k rpm, and it sounds very similar to yours(rattling a can of spray paint). It does not make the sounds when I rev the car in neutral, only when I'm driving.

Could this be the pre-cats also?

 

Check all your heat shields first.If you have access to a lift it will be alot easier.Have someone under the car while your in it holding the rpm where it rattles the loudest and have the person underneath chase where the noise is coming from.

 

Noooooooo! The FUD is growing to devour the senior members now!?

@Nmex: That scale is pretty sweet, but could you toss a few 6's or 7's on there so I can have a slightly better understanding..?