well now.... i had this problem start a while ago during winter. i was rearended when it was slick. some guy in a riced out civic. slid right under my car. no apparent damage besides for knocking off my spare tire and license plate. he also knocked my exhaust off the mount on the rear which i thought was no big deal. a month later it started ratteling under my truck. once it warmed up it stoped so i figured it was just the cold. now i realized that my cat is going bad very fast. another reason i think its going bad is my gas mileage is decreasing alot and im only getting about 13 mpg. i think i read on here that once i change it it should be much better.

could this have even happened from the guy pushing my exhaust in a bit?

either way i have to get a new cat soon and im thinking about going with the magnaflow. get a nice tone out of it while im at it.

let me know what you guys think and if thats a good idea for a new cat.

 

I'd check for codes to make sure it's the cat that's bad before replacing it.

 

I had a rattle I couldn't track down, thought it was the cat or clutch but it turned out to be just the universal joints.

Does it sound like someone shacking a coke can with a marble inside?

 

its only at idle. and i just replaced a ujoint that i know was bad. so its not that. i can clearly hit my cat while under my truck and hear it rattle.

 

if it is the cat, sounds like a good excuse to get a new magnaflow high flow cat

 

precisely!

so after shopping around, the shop that installed my muffler wanted 500 total because they wanted me to get a whole new setup not just the cat. so i said screw that noise and i would just learn how to weld. well i called another shop around here and they said they could install an universal one for 88. boom. gonna go ahead and order the cat soon as i get paid. does anyone know the size for the inlet and outlet? i believe its 2.5 in and out. but correct me if im wrong.

 

So are you for sure getting a magnaflow cat?

 

well thats what i saw posted in another thread somewhere. thats the only performance one i can really find. and its only 65 shipped so i figured that would be my best value. is there another brand i should buy or are you just wondering how its going to sound?

MagnaFlow 99006HM - MagnaFlow Heavy Metal Catalytic Converters - Overview - SummitRacing.com

here is the cat i think im going to get. the shop said 88 or whatever it was for a universal fit. i have no idea how much they would charge for a direct fit but im sure it would be more and the pare is also more so im not gonna go for that. this one seems just fine!!! MSRP on the magnaflow site for $232!!!

 

I just got a new cat put on my truck. It was rattling so bad and my fuel economy suffered just like yours. I also was throwing about 5-6 codes. I plan on writing an entire excerpt on my experience just for a reference in a different post.

Anyway...I read a lot on the forum about exactly what you are about to do. I put a Super 44 on my Blazer about two years ago and it sounded ok. I wanted it louder/deeper but I just let it be. Well, when I knew I needed to replace my cat I also researched the idea of a Magnaflow high flow cat. Many things I read said its a waist of money. Some also retorted that ANY after market cat would do the trick and have much higher flow than the OEM. I trusted the many posts that I read and had my local shop put on (I hated doing this but I had no time and had to drive 400 miles the next day) a universal aftermarket cat. They cut the old one out welded new one in for $220. Out in 45 minutes.


Result: No more codes! Awesome power - I dont know if there was a gain or it just felt like it because of how crappy my power was before hand (terrible). And, now my exhaust sounds perfect. Much louder, throatier and a perfect rumble at idle.

**Edit: My fuel econ is also superb now (respective to what it was before)

Anyway, take it or leave it but I was super thrilled with the results. I also found some high flow cats for about $80 on the internet. Had I had the time I would have just bought one of those and done exactly what the shop did. If you have access to a chain cutter, GET IT! It will make your job so much easier with a perfect fit.

Good luck

 

hey man. thanks for the great advice man. i would weld it in myself but i dont know how to weld or anything like that. and i figured 80 bucks is a good deal to have it done by a professional who i know will do it right the first time. what kind of cat did you end up putting on your truck?