Odd Sound driving me crazy and getting louder
 

So it sounds like I have a loose wrench lost in my engine bay.

I have all my wrenches accounted for, and lots of searchcing hasn't found anything else loose or dropped. But that is the sound I am hearing. When I just pop the revs from idle, and when the revs are dropping back to idle under braking is when I hear it. 1, 2, or 3 clanks like a wrench striking metal. I'm guessing something is loose, and it happens with 'low frequency' vibrations of low revs.

It isn't the 'tin' rattle sound like a heat shield, definitely more 'solid' of a clank. Any ideas? I can't get it to repeat while stopped more than once, still trying to get it on video.

It's incredibly inconsistent. Occasionally I can hear it when the car is stopped, but never more than that 1 time. I usually hear it after coming to a stop (only like the last half second before I stop), like a red light or stop sign, then again when I pop the revs slightly to start moving again. But I don't always here it there either. Once I hear it in any given car state, I never hear it again until after I hear it in another car state.

It does seem that I am more likely to hear it after putting higher lateral Gs on the car (forward back mainly, usually am no where near stopping locations when I can do that side to side).

Almost like something is loose, and moving or higher revs gets it aligned correctly again, until a higher lateral G knocks it out of place. Almost. I'd have a hard time calling even that much of consistency.

All stock as far as I know. 55,950 miles on the odo. 2005. Bought it with 8,400 miles on it, so doubt the prior owner modded the clutch.

Exhaust touching one of the crossmembers?

Not that I can see.

But then again, it's dark outside. I didn't notice anything odd when I was under my car earlier today. Been happening for a week or so now. I'll check again tomorrow specifically for that. It definitely sounds 'forward' of me, not below or behind, so not sure that would fit the sound direction.

Any loss in top end speed = butt dyno?

Yes, but I know I am running too rich, and I believe I have my front O2 sensor failing, so hard to pin my loss of power on anything but that right now.

I got a scanalyser in over the weekend, which should confirm that problem, but waiting on a tech support response, since I think I got the wrong software app with it.


You thinking that the sound is my apex seals? :lol2:

05 version (possibly an 04 build date?) with 56K on the clock - it wouldn't be unheard of.

Sorry, meant that as a joke. No chance it's my apex seals flying around in there. I only have slight power loss, and I can definitely tell I'm running rich. Other than that, I still have normal start times, great throttle response, 21mpg (vs 24 in perfect condition, one way I know I'm running rich) etc... I will have the rich condition diagnosed before too long, as soon as I can get the scanalyser working.

It's not my apex seals :)

It isn't connected with wheel speed, gear speed, and only indirectly RPM. The rattle is only heard when my car shakes the absolute most (which isn't much), right at low RPM just above idle, and in any given state, once it rattles once, it won't do it again until I do something different with the car, and it doesn't do it every time anyway. Didn't do it at all today to and from work.

check the front wheels brake lines ---from the abs system to the wheels. The right sided line (passenger) has been known to vibrate agaisnt the chassis --where it turns at the engine bay down to the passenger side brake caliper.
OD

I think I have this EXACT same problem! I have an automatic though, do you have the stock exhaust system or an aftermarket one? I think it might have to do with the exhaust otuching something and causing loud vibrations. Can you almost feel the banging by your pedals? That is where my sound seems to come from most of the time.