Hi guys, I’m pretty new to the site as a member but have used it before with figuring out problems with my 8 and troublenshooting. But I’m having a hard time finding this issue. I get this flapping noise sometimes during acceleration. Not every single time but a lot. Especially under higher load. But it will stop once I even out and reach a cruising speed. I had called rotary engine specialist in Canada about potentially gettin a new engine cause this bothered me. I was told by them it COULD be the cat.
Mom mot overtly knowledgeable about the car but I can figure stuff out and get stuff done. But I don’t wanna purchase a $5k engine if it’s not the engine. But it could be and I do t wanna take one guys word who couldn’t see the car that it’s just the cat. That’s an easy fix with a mid-pipe. But if it’s something else......What could this be?? I am thankful for any help or insight I can get thank you so much

I do have CEL codes p0442 p0455. I think may have to do with cat or gas cap for those. But as for the flapping I don know how else to put it. Almost like a knocking but not quite. I’m fairly certain isn’t the motor as well. Car runs pretty good gets up to 130. Doesn’t seem to have a whole bunch of lost power. Sluggish maybe getting up to speed but not powerless.

Also it does not sonthis constantly I haven’t tore my engine bay apart but I have done work to the car since buying it and I do not believe anything is loose or about to fall off. I will check to see though. I’m kinda hoping that it is the cat cause of how easy a fix that would be. And since that’s what rx7/ rotary engine specialist said it was just by me telling them exactly what I said here. He didn’t even hesitate just said “ oh it’s the cat, it happens a lot we get that all the time”. Though his confidence was reassuring, it also seemed a little quick like he might have just said something to get off the phone. I’m not sure. So I’m just seeing if anyone else might have an idea

I’m trying to find a way to post a video