Goodday Rx8 members, I own a 2004 Mazda rx8, we recently replaced the engine, the engine kicks well but the problem is with the "marble in a can like noise" after starting the car even if its in a stationary position, wat could be the problem. Compression is OK.. Your help will be highly appreciated.

 

There are beaucoup threads for MIAC.
A common problem.

 

There's only really 2 things, you don't have the restrictor in the heater core hose. if it sounds like it's in your dash.

or you have a blown out cat if it's under the passenger seat or the back of the car.

Search aroudn a bit and you'll find the threads.