Weird "Knocking" noise from under car **HELP!**

[cgrant]

It almost sounds like there is something stuck in my exhaust pipes...which is...impossible unless something snapped off instead the heads


Anyways, exhaust has been on for like 2.5 months now and never made a noise, now there is a "knocking" noise that is very audible from outside and inside the car.

When laying under the car while it's idling it almost sounds like it is coming from inside the cat....

Now, I have a bassani xpipe with the bassani(ofcourse) cats, and have heard many bad things about them....Could this be the problem?

Also, sometimes the car will "chug" when I first get out of the garage...will chug for about 4 blocks then be fine for the rest of the day.


2000 GT with only 15000 miles

P.S. - Does NOT sound like an exhaust "tick" from a leak....welds were checked and headers are still on tight. (plus it doesnt sound like a tick ;p)

 

[twogts4us]

Have you tighened everything up on the exhaust? It's not uncommon for the bolts to loosen up all by themselves.
By the way, how is the Bassani X with cats and Flows? Now, obviously, you have the mid lengths as well, but, with the limited choices for catted H pipes, I have been leaning toward the Bassani - and at about $360 (for the nonSS one), it's a bargain. I love the sound of flows and have heard some say that they work best with an H pipe. Just wanted to hear what you thought.
Sorry, didn't mean to whore in on your thread...!

 

[stangman]

It almost sounds like there is something stuck in my exhaust pipes...which is...impossible unless something snapped off instead the heads


Anyways, exhaust has been on for like 2.5 months now and never made a noise, now there is a "knocking" noise that is very audible from outside and inside the car.

When laying under the car while it's idling it almost sounds like it is coming from inside the cat....

well noises can easily travel in a car, so i would get a stethescope & try to track it down that way. starting at the valve covers & working your way back to the cats. at least that is what i would do

Now, I have a bassani xpipe with the bassani(ofcourse) cats, and have heard many bad things about them....Could this be the problem?

usually if a cat gets clogged, it will be red after a good drive, because all the exhaust gases being trapped at it

Also, sometimes the car will "chug" when I first get out of the garage...will chug for about 4 blocks then be fine for the rest of the day.

change the fuel filter mine did the same thing. i changed the filter & viola no more hesitation

 

[cgrant]

change the fuel filter already? only 15000 miles

 

[stangman]

change the fuel filter already? only 15000 miles

yup, "technically" you are supposed to change it every 15k miles anyway some need to do it, some don't. i was one of the people that needed to, prolly cause we had some bad gas work it's way into our area so i've been told