Installed Ark Dt-s Catback
 

Installed my ark dts catback couple days ago and the problem is when i started it today everything was all good until later on today when i was parking my car it seemed it was going to die like if you missed the clutch shifting.

ex your in idle engine is warmed up, and you rev it up and before it revs up the rpms dropped down first almost like if you missed shifting and engine is going to die but then revs up after that. happened a couple times. i went back to try it again worked just fine like a normal rev. Is this because i dont have a tune yet or my car adjusting to the new exhaust. Going to get a tune soon.