Re: Very Strange Noise.. HELP!
 

markdoddridge do ya know if its the cat coming apart? or is it just the heat shield rattling on the cat? If its just the shield rattling on the cat that is usually an easy fix with a band clamp.No need to replace. if the cat is coming apart itself it does need replacing. Would be alot cheaper just gettin a band clamp or two and some seafoam to clean the fuel system.

ETA im no mechanic but with those issues i just dont see how this vehicle would be considered unsafe. im sure someone with much better knowledge of hummers than me will chime in soon enough.

Re: Very Strange Noise.. HELP!
 

What month in 2004 did the truck go 'In Service'? GM has an 8 year/80,000 mile warranty for the catalytic converter but "the applicable warranty period shall begin on the date the vehicle is delivered to the first retail purchaser..."

So you may be able to, based upon mileage and in-service date, get it replaced under warranty.

http://www.justanswer.com/uploads/mc...l-Warranty.pdf

Re: Very Strange Noise.. HELP!
 

Thanks guys, but my truck has 90k miles already. Both the dealership and Titan said the cat needed to be replaced so im inclined to believe them. Although its possible a clamp could have fixed this, if i knew more about engines i could have probably found out for myself