theres a terrible grinding, almost as if something were dragging. its most noticeable in the low rpm range. we thought it was a heatr shield on the small stock cat, so we took it off and the sound stopped for about an hour, ten started again, so i guess that wasnt it. it sound like something rattling around in the exhaust near the cats. i have a 5sp 91 tt Z. im about to take my Z to nissan and have them rape my wallet to look at it. any ideas before i do that???

 

I don't have any answers, but isn't there a shop that specializes in Z's somewhere by where you live? The dealership WILL rape you and it won't be quick. Look around for a reputable shop. also, do you have stock exhaust? Is so, you may have a bit of a rust problem, just a guess, but try hitting your exhaust (not too hard) and listen to see if it's rusted.

 

Main exhaust inclusive of main cats are fairly easy to remove (18" jack stand clearence and "Blaster" lube on the downpipe\main studs.

Pull the exhaust and inspect. Great opportunity to gut the main cats if the pipes have life left without too much corrosion.