Okay , i bought my 04 RX-8 about 2 months ago, ive replaced the vacuum sensor, throttle body , all fresh plugs wires and fluids. And im still having this problem, CEL comes up at high idle and IMT VALVE STUCK OPEN. anyone point me in the right direction?

 

Vacuum sensor?

One of the intake valves is stuck open, usually the SSV. It's in the lower intake manifold and can get gunked up. You can try to free it by hand by moving the actuator, but the proper solution is to take it out and clean it.

If you've replaced the spark plugs and wires, you should probably replace the coils as well. #1 killer of RX8s.

 

post the actual CEL code if you want help

 

It’s P2070 I’m sure. Clean fuel injectors would be the easiest plan of attack. That may be the issue as that code can indicate clogged fuel injectors. If it’s not that then I would suspect an issue in the intake manifold. Could be difficult to fix if the fuel injectors are working fine.