Shift from 4th to 5th and Pop

[SoloRanger]

Ok so, something odd recently started happening a few weeks ago I got my exhaust redone with a cherry bomb muffler , long story short it was running great sounded good, and then with in the last two days if I'm at WOT and I shift form 4th to 5th I get this odd pop sound from the exhaust.

 

[SoloRanger]

Shocked first time I got no thoughts on a problem lol

 

[E4Ranger]

if the new exhuast is less restrictive, the engine may need to be retuned for it. dont know how exactly with fuel injection, maybe a neew chip?