I purchased my 04 RX8 last year (2012) (my second rx8) and one of its rotor blew...

Had the engine replaced, brand new from Mazda, put in an Injen intake system, Agency Full exhaust system with agency mid-pipe.

Just about to hit 1000miles on the new motor. The check engine light is on due to no cat, however recently I have been pushing the car a little more as I break it in more.

When I am on the highway driving at higher speeds, as compared to local streets, sometimes around 6-7k rpm the car sounds like I am redlining it to 10k rpm, the check engine light flashes, and coolant light comes on and then smoke out of the rear... honestly I can't tell what color because my car is tinted (hahaa) ...

after a few seconds, everything stops, smoke goes away, coolant light goes off, and everything is back to "normal"....

any ideas fellas?

 

See my sig.

A flashing CEL is ALWAYS a misfire. Always always always.


Coolant light is probably coming on because you are low on coolant, not critically low, but low enough to trigger the sensor at higher RPM.

 

You should get the codes read, to see what might be stored in addition to what's there from having no cat. That might point you to the reason for the misfire.

The coolant light may not be providing useful info. It's reasonably common that when the sensor goes bad and is intermittent the light will come on at high rpm. I don't think anyone has figured out why. See the coolant bottle thread(s) for entertaining tales.

Smoke is very rarely a good thing.

Ken