went to the local muffler shop today to see why my cat is showing up as bad on the ole fancy computer. they hooked it up to some kinda gauge and said i didnt have enough back pressure. how is this possible when ive been running the same setup for over a yr now and all of a sudden the light comes on and they tell me its messed up. are they feeding me a load of garb or is this a possibility that somehow or another i have misplaced some backpressure. where did it go? how can i get it back? dang it it was my backpressure to begin with so how do i get it back? is this what is causing my fuel economy issues? someone help please before i have to drop some cash into something that someone told me was broke  

What year? What model? What engine? What exhaust? Tell us what you are dealing with and we will be able to better help you...  

sorry 03 tj factory exaust with a 12" glasspack thats been on there a year before i had any issues. 4.0 motor.  

the packing is probably burned out of the glasspack...which creates less backpresure.
It's been my experience with glasspacks they don't last long.

Isn't it a bit louder than it was a year ago?  

get rid of the cherry bomb and put a flowmaster or equivalent on and you wont have that problem again...and youll be happier w/the sound too.  

Glasspacks are cheap because they don't last. Go with a flow master, or some other turbo muffler, you'll be much happier in the end.  

went to another muffler shop today for a second opinion. sorry i work in the medical field. always have to get a second opinion. this guy is telling me that there is too much back pressure. should i just go ahead and replace both and hope for the best or go cheapest first and hope that fixes it  

lol, must be the other dude's brother!  

if you go and replace w/glasspacks again youll be in the same boat again in a year or so...you need to stick w/a muffler that last longer than a year so go w/flowmaster like i mentioned above, ive run flows on all my rigs now for over 10yrs and havnt had a problem w/them.

now i can relate to your delima w/one dude saying no backpressure and the other saying too much backpressure,you see i have a bad knee w/a huge bump on it now for over 20yrs from skateboarding and one doctor says i need surgery to fix my pain and got a second opinion and the other dude says i need to loose weight that im too fat and my knees wont hold my fat asss up, so what do I do? these guys might be bros too!  lol  

I'm with these guys... put a real muffler on it and see what happens...  

What was the Code? if it was a Catalitic Efficiency code that doesn't mean anything about the muffler, it means it is reading to much oxygen at your cat. take it to a pro and have them diagnois your jeep right, throw parts at it will not be the cheap way to go, more than likely a problem with the cat or the engine than the muffler unless the welds are braking or a leaking gasket and you are getting air in the exhaust stream.

Michael Berg
ASE Master Tech  

the code was low catalyst eff. bank 2 p0432  

http://www.jeepsunlimited.com/forums/showthread.php?t=721761

read the whole thread!