Bad CAT? Bad Y-pipe? Bad Clamp?

[P-nut-]

I have the same problem now on my 2000 v6. It started last night with severe power loss. This morning it ran fine until it started to warm up, and it warmed up unusually fast. Now the rattling of the cat is beginning to get noticeably louder and louder. Luckily I work at an automotive shop and I had 2 technicians look at it this morning when I got here. Both said the same thing, clogged cat. Whcih would explain my power loss when its warm, and why i cant accelerate past 4000 rpms without is sounding like its going to fall apart. All the backpressure is killing my accelereation, which is also why it warmed up so fast. I think I'm just going to gut it until I can get a whole new exhaust to prep for the BATMAN superchager setup!

[whtefbrd96]

Yeh the seal in the front of the differential is obviously a problem, mine was replaced befor i bought it and they told me so they saw it in their 124 point inspection. As for the ratling.. it sounds like you had the same problem i had and i couldnt figure it out so just said F it. When i change dmy spark plugs i took off my heat shield off both sides of the manifolds i when i got finished put it all back together a week later i realized WOAH NO RATLE !! just spray some PB blster on the nuts take them off make sure nothings bent put them back on tighten up and see it that will help you. It only takes 15 minutes worth a try. Oh and it didnt seem like the ratle was coming from there when i was trying to find iteither. Just a thought!

[knowledgefreak]

<blockquote>quote:</font><hr>Originally posted by Bluefury99V6:
Well I got underneath the car today and couldn't narrow down the vibrating noise to the CAT or to the shield that is around it. However I did see that my rear end is leaking bad! :eek: It's leaking right where the drive shaft connects to the rear end. I'm over my warranty by a month and have 35K miles. I gave Pontiac a call and they said to take it into the dealership and have them look at it. After that I'm supposed to give Pontiac a call and they'll tell me if they will repair it under warranty or send me up sh#t creek. This is my second Firebird. My first was a 91 and 3 years after that (12 months of payments left) warranty went out that car went down hill. Almost like they build them like that. That one started out with a starter problem and they fixed that under warranty. Then it just went to hell. I lovingly refer to my 91 red WS-6 formula as Satan. I hope this isn't a repeat on this car. This car is my fourth Pontiac and fifth GM car. If they do me wrong and this car goes to sh#t too, I may turn to the dark side (something other than GM).<hr></blockquote>

Don't take it to the dealer, your seal on your differential is just bad most likely, take it to some tranny shop and have the fluid changed and a new seal put on for cheaper.

[Original 4th Gen V6]

I had the same problem but it was around 70,000 miles. Ive heard a lot about the heat sheild rattling, if that is so just bend it out of the way... My cat converter was bad so I replaced it, when I got it off and shook it, everything inside of it was free to move around...I had the same problem as you though in that it only rattled sometimes. Cats are supposed to last 60k+ but it sounds like that could be the problem.

[Shadly]

<blockquote>quote:</font><hr>Originally posted by P-nut-:
This morning it ran fine until it started to warm up, and it warmed up unusually fast<hr></blockquote>
I had the same problem. I took it to the dealer to have it replaced. Smog parts are covered for something like 7 years. I also had a rattle in the heat shield. I took it off, glued cork gasket material to the back side, and reinstalled it. It seems to work. Now I have a Y-pipe issue. What a headache!

[V6Maniac]

I too started noticing a strange clicking noise underneath the passanger side of my car. I started noticing it was taking a lot more gas to get my car to accelerate and it feels like there's a delay before it will speed up. Is it possible my cat is clogged and if it is what's involved in "gutting" a cat? I'm not to worried about immissions they never inspect here in kentucky and if they do... I bought it that way hehe. Any help would be appretiated. I'm going to have my new exhaust installed tomorrow and if my cat needs to be gutted or whatever, they could probably do it.

[Bluefury99V6]

I just talked to Pontiac. They will fix my car under warranty :cool: My car was out of warranty due to time by a month. The dealership found loose pieces inside the CAT and said it was partially clogged. It never set off the SES. They will also replace the pinion seal and some other seals that are defective on my rear end. I'm really happy that they helped me out. I was disappointed about the rear end though. The car is my daily driver. I don't rag it out and don't race it. It's only a V6, no NOS or anything. I guess LS1's must really chew up the rears ends if they fail mated to a V6. I was a little nervous that they wouldn't come through for me. I just bought a 2002 Impala LS for my wife a month ago too. While my Firebird was in the shop I went over to the Ford dealership and looked at some Harley Davidson F-150's and a Lightening. Ford sure was anxious to come through for me if Pontiac didn't. They offered me a $11k trade without even seeing my car. The GM dealership only offered $9500. Oh well I'll keep my car since its getting close to being payed off. If it breaks again before it's paid off then I'm a chump for not getting rid of it now.

[P-nut-]

I had my cat gutted anyway, even though it would have been covered under warranty. Heh.. oh my god. My car has never had this power before, especially above 4000 rpms. It just keeps pulling. Low end has improved too. No I just need to figure out the pieces that I need to redo my exhausts and all. Anyone want to tell me what I should look for? Headers, y- pipe, i- pipe?