im 18 and just bought a 2004 auto rx8. it has 102000 miles with a new engine at 60k. in the last few days iv noticed that when im at a complete stop with my foot on the breaks the car vibrates and makes a loud vibrating noise and then dies down a little bit but starts back up. it will go away if i put the car in park but does the same thing if i let off on the brake and pull the emergency break. it also does it for like a second as im shifting it into drive and start driving away. it also has a flowmaster exhaust on it idk if this has anything to do with it. i dont know if this is common or how its supposed to be. i just need some help. thanks

 

Sounds like a bad motor mount.

 

how bad is that? and fdo you think that since it was a factory replaced engine it would be under warrenty?

 

^^+1 Bad motor mount. Its gonna cost you a couple hundred bucks at the dealer.

 

Welcome,

Could be a mount, like stated above... Before that, I would check the MAF and clean it. I would also look hard at the $100 thread below. Mine ran like that, a combination of the stuff below seemed to sort it out. I would suggest MAF, and attend to grounds. Save cooling until summer. You are also ripe for plugs and coils.

After MAF, I suggest an ECU reset as well, either disconnect battery, or turn on car (not start) and pump brake 20 times fast. Look for the oil pressure gauge to move to tell you it worked.

And, again, welcome.