let’s say I am going 55mph cruising sometimes it will be bouncing like 3k then 2.5 then 3k and 2.5 at the same speed and same pedal just bouncing, and u can hear it too like the engine get louder then back to normal

 

@55mph, 25%- throttle, you should not be @3k in OD. Do you have a tuner installed?

 

my ecu is tuned by James from Supermodulation

but the car was running fine before it just recently started doing that

 

I don't diagnose mods! Your original post was driving @80mph(3k about right in OD), however, driving in 3rd @55mph would be around 3k, when OD locks in, RPM'S would drop! If you are locked in OD, and the rpm drops, I would check fuel delivery. Btw, I only shift to D, when I drive on the highway +55mph, a way to prevent premature wear on the transmission, 3-4 shift is between 45-55mph.

 

well it’s random sometimes 55 sometimes 80 it’s at random speed . And what u mean shift to d. It’s automatic I have to have it on d to drive

 

Yes you can shift an automatic transmission, 4 selections:

 

Oh interesting but see I didn’t had that problem until recently with the rpm bouncing :/

 

RU driving like you stole it?

 

lol no sir I baby the crap out of her

 

Ok, that's not it. Did you scan and check for codes stored? RU using top tier gas?