Acceleration/Deceleration/Throttle Rattle/Crackle Sound (1 Viewer)

[Shoalwater]

I've been trying to figure out a sound on my '96 LX450 I've noticed when I put on or let off the throttle. It's not insanely loud, but it sounds like metal rattling or crackling. I've noticed it more in summer since I have the windows down a lot - it's not so bad that I can notice it with them closed unless it's really quiet at night and I am giving very light throttle. It really seems to be connected to throttle, I don't notice when I'm coasting or stopped.

It's a 23 year old vehicle so I know there will be some rattles, but this one seems distinct from the rattle of a worn-out or loose heat shield that I have read about here through searches.

I've greased the spiders and slip yokes, doesn't seem to affect it. Searches say it might be U joints - it's possible they're shot and need to be replaced? I have tried to find videos of what those sound like when they're gone but it doesn't sound like what I am hearing.

Any input? The noise is just above the "it's not that damn bad, just deal with it" level and I would like to address it, especially if it's something letting me know that it's wearing prematurely or needs to be replaced. Thanks.

 

[shocktower]

Check your birfeilds and see if they are dry, to do this you remove the square bolt and stick a zip tie in the hole and see if it is dry and if so get some molly base grease and pump it full, or you maybe ready for Birf service . If it is not that check your heat shields and the very back little muffler, Oh yeah check all of your exhaust rubber mounts they maybe done too . Ok I thing I have covered pretty much what I think good luck . Oh s*** you live in portland L0L I just saw it, sooo if you need help I live in Canby Oregon

 

[wakesetter]

Check ujoints

 

[Tedward]

You could try the old remove one drive shaft, lock the center, and drive test.
Divide and conquer

 

[BILT4ME]

Probably an exhaust leak because it cracked at the wye or the O2 sensor nuts have rusted off and blowing the sensor out of the hole or the exhaust is shot and needs a new catalytic converter.

Or just heat shield rattling. Or your fender flares are vibrating on the body from the wind

 

[Sc0-]

Had a similar issue and thought it was the internal of my cat converters falling apart, ended up being a heat shield on the pipe leading to the cat converters. A few years ago I removed part of the heatshield because it was rattling, this was a similar piece that was cracked and rubbing against the pipe.

 

[Shoalwater]

Hey, thanks to everyone for your suggestions here! I was out of town all weekend and coming back to a bunch of ideas is really helpful.

Sounds like I should use some hose clamps on heat shielding and see if that causes it. Also remove the drive shafts, although I'm such a sub-one banana mechanic that it's a little intimidating to think about that.

Will also check the birfields - I haven't done any greasing there. I haven't been super concerned about them as I haven't had any weird sounds or feelings turning the wheel lock to lock, or heard any clicking when turning which I have read are telltale signs that they're shot.

With regard to checking the U joints, what should I look for? I have done some reading on generic car forums on how to tell if they're bad and I don't see any of the signs of wear around them or grease leaking or anything. Would that be part of the drive shaft removal, that I could inspect them then?

@shocktower thanks for the response, I may hit you up if I can't figure this out! Also want to get together with some cruiser people locally. I have looked at the Portland sub forum and just haven't made it to a regional meetup yet.

 

[lky21]

Did you ever figure this out? The sound is intermittent but I may be having the same issue.