Sluggish Acceleration

[GulfCoastTahoe]

Specs:
2002 Tahoe
5.3L V8
No engine mods
Turn down Super 44 Flow master Single in Dual out

Problem:
Since about two weeks after adding the Super 44, I've had sluggish acceleration around 20-45 mph. My main question, is that if the welds are faulty, could I be losing back pressure via the exhaust?

What I've done:
Cleaned the carb/intake
Cleaned the MAF
Cleaned the Air Filter
Tightened all intake clamps and checked seals

What do you guys suggest?

 

[ccapehartusarmyINF.(ret)]

probably not losing back pressure but you mite have a leak upstream from the cat wich would affect your mixture causing you to lose performance at low RPMS

 

[Blazed]

In the past I've been able to feel power differences when going to cat-back to no exhaust temporarily and noticed a lack of power in certain spots. I believe in the "back pressure myth"