So my 04 rx8 (MT) with 112k miles on it is having issues when shifting at high rpms.

It started a couple weeks ago with a rattling sound coming from under the car at low rpm at low speeds and also during shifts at low speeds.

A week ago I gunned it in 1st, redline shifted into 2nd. During the shift I hear a pretty loud pop sound coming from somewhere under the car and I look in my rear view mirror and I see a big puff of white smoke on the road right where I had shifted. My first reaction was something with the tranny or the clutch since it happened during the shift.

Anyways for the past week I have been babying the car and it works perfectly, in fact the rattling sound that was there is no longer there.

Today I redlined it in 2nd going onto the highway and when shifting, I hear the same popping sound coming from under the car and I look back but see no white smoke behind the car. I wasn't sure if it was just because I was going 70ish mph at that point and the smoke would just clear up quick enough for me not to see it.

Anyhow, I was hoping maybe someone here has had or knows someone on here that has had the same symptoms and what they did to fix it. Is it possible it could be the cat or is it something in the drive train or maybe the engine itself

 

1. Any power loss or revs doesn't climb smoothly?

2. Any signs of oil in coolant tank?