Okay, so this started happening after I modded the stock exhaust by swapping the mufflers for performance mufflers. The car basically doesn't want to change gears on time (If I want to cruise and not speed) I get put in this weird situation where the car keeps reaching higher RPMs until this weird sound occurs (When the car makes this noise, I'm still in the gear, and I have to give it gas to finally change onto the next gear. This happens most when the car is fully warmed up and usually transitioning from 4th to 5th or 5th to 6th. I've looked up what "rev hangs" are and they usually happen for manual transmissions. I have a feeling what I'm experiencing isn't exactly rev hang but maybe something similar. Hope someone knows what I'm talking about!