SemtexXoutlaw

I recently installed some long tube headers (no cats) on my 5.3 2013 GMC Sierra. I had a Borla XR1 and a street tune before the installation. I have not had the truck retune because the guy who tuned it is no longer at the same shop and I have been on a mission looking for him. The truck sounds great at start up and idle but when I step on it seems to make a loud kind of backfiring sound and that goes away once I get to 3 gear or so. Would this because I have not had it retuned or could it be misfiring? Any help would be greatly appreciated. Thanks!

LETHL_SS

iTrader: (23)

Did you removed the spark plugs before you did the install? If not, you very well could have cracked one or damaged a plug wire... it's easy to do.

SemtexXoutlaw

I had them done at a muffler shop so I'm not sure. Maybe I should take it back to them..

chewbaccav8

Just my opinion, maybe have it re tuned. Could work out the bugs.

Txblue

iTrader: (1)

I put long tubes with no cats on my brother in laws 2010. And it drove fine for about a month other than check engine light on due to no cats before we had it tuned. I'd get it to a tuner to see what codes you have.

LETHL_SS

iTrader: (23)

It's unlikely the tune would be off enough to cause a misfire just from some long tubes especially if it was street tuned before. Yes you must get it tuned and the sooner the better but a plug and/or plug wire is most likely the issue.

Off topic but I'm really surprised a muffler shop installed headers without cats... They can get crazy fined for that.

Jason Z69

Does it have a hollow or packed muffler

SemtexXoutlaw

I had the truck re tuned and it still makes the sound. I think it sounds that way because of the muffler or because its a 5.3. I been reading that others add a bullet in front of the muffler.

vettelovralexand

Take a listen to my 5.3 with catless headers here: https://www.youtube.com/watch?v=WT0FHvMouf4

Mine didn't make any popping noise pre-tune, post tune, or post supercharger. Always has sounded like the video, that is with a corsa sport dual rear exit.

SemtexXoutlaw

Well i ordered me a oval Borla to replace the circle Brola i have now and hopefully that fixes my issue with it.