Car is giving me a headache :(

[TheWizardofOz]

So I've worked out some of the problems I was having with my car, but not all of them. I still have the metal sound that I described in another post, and I can't for the life of me figure out what it is. It sounds a little like when my cat went out, like a very fast metal rattle. It sounds like it's coming sort of from the center of the car just a little in front of me, but it's hard to tell. It does it much more when cold, but not always when it's cold and sometimes when it's not cold. I just replaced my MAF sensor with a new one because it was throwing a code, and now the code's gone. That seemed to make it happen a little less, but not go away. The car still feels like all the power is there, but I've had the issue for a while so I can't really be sure.

Some other things I've noticed that may or may not be related:

-Sometimes when I let off the throttle, it will drop only to about 1200 RPM for a second, then kinda go "vroomph" and coast like normal.(Surging?)

-I've had the problem for a while, it's just starting to get worse and louder recently.

-Sometimes after I turn the car off the motor will stop, and then a moment later I'll hear a kind of clunk. I thought this was normal, but I'm no expert. I also got this sound to happen once after rolling it about 5 feet in neutral then putting it back in park with the engine off the whole time.

The car is a 2000 A4 Firebird.

Thanks in advance!

[vr4gasm]

Re: Car is giving me a headache :(

heat shield?

[TheWizardofOz]

Re: Car is giving me a headache :(

Thanks for the reply. I think I've checked all the ones I know about, I'll go over it again either tomorrow or Sunday. Theres one on the cat, one on the starter, and one on each exhaust manifold right? am I missing any?

UPDATE: I checked the heat shields I know of and they all seem solid. I found a dry rotted piece of rubber tube about an inch long around what I think was a connector from a metal section to a rubber hose on what I think is a coolant line. I'm not sure if that's where it's supposed to be or what it does. I also checked coolant and I'm low and there's this sandy build up on the dipstick. I don't think it's related, but just wanna make sure I give as much info as possible.

[nimrod.sixty9]

Re: Car is giving me a headache :(

Make sure to check that heatshield thats on the firewall, I believe passenger side. Also check around where your Y-pipe bolts up, to the manifolds and cat back...

[chevy3504me]

Re: Car is giving me a headache :(

I had a problem like that. It was the bracket that connects to the exhaust and a mount near the trans mount. Check to see if that is cracked or broken. Wish I could give better advice but its been a few years

[TheWizardofOz]

Re: Car is giving me a headache :(

Thanks everyone, I didn't know about the heat shield on the firewall, I'll check that out tomorrow. I'll also check around the trans mount to make sure everything's ok there.

[chevy3504me]

Re: Car is giving me a headache :(

The bracket on my car was near the cat. I broke it all the time and had to keep welding it. Shift to hard I guess. might have to get sub frame connectors hahaha

[TheWizardofOz]

Re: Car is giving me a headache :(

I checked the bracket that goes to the cat and it's still welded there. I couldn't find a heat shield on the firewall, unless you're talking about the one at the very bottom passenger side that wraps under the car and over the cat. I couldn't find any problem around the Y pipe but I'll check again, I didn't have a lot of time.

[97rs4life]

Re: Car is giving me a headache :(

tap your ypipe and see if you hear the rattle, that ypipe is not single layered ;) At least my 97 I know was double wall. Maybe the interior piece is rattling

[ssms5411]

Re: Car is giving me a headache :(

tap your ypipe and see if you hear the rattle, that ypipe is not single layered ;) At least my 97 I know was double wall. Maybe the interior piece is rattling

Thats what mine was doing the pipe under the oil pan was doubled walled and was leaking and rattling.

[TheWizardofOz]

Re: Car is giving me a headache :(

About how hard should I have to tap the y pipe to get it to rattle? From inside the car, it sounds like that's about the location the sound is coming from, but when I got under the car and tapped it with a hammer it didn't sound any different than any other pipe. is there a specific section that's double walled? I should be able to get one of my buddies to help me either Wednesday or Thursday, maybe with an extra pair of hands I'll be able to tell for sure.