i posted a thread a couple days ago asking what could be wrong with my rx8 and ill give the rundown of what has happened..
i was driving down the road and i noticed it started running bad and noticed smoke/overheating and i pulled over and lifted the hood and smoke poured out and i saw that the headers were red hot along with the catalytic converter..
on the previous post i was told that it was either running lean or the catalytic converter was just screwed up..so with the motor being a brand new crate motor that i recently installed a couple months ago assumed it shouldnt be an engine problem with that i maintain the oil with adding it every so miles and replacing it...
i replaced the catalytic converter(which it did have loose internals and the honey comb shaped things falling out of the old one when being taken off) and it is still running the same and rough like a golf cart put put feel..not a bad compression feel like i have felt before i replaced the motor.
i need help considering that this is my daily driver...

 

If the cat was so bad that it was falling apart when you took it off it may have clogged your catback

 

i was also informed that it could be a bad injector or coil pack..shouldnt be that severe though..?

 

You may have burned up the new motor, run a compression test.

 

it is a p0300 and p0301 code being thrown

 

have you tried checking your fuel pump, spark plugs, and checking your coolant level, and quality?

 

+1, no sense in replacing more parts. You may want to start with checking vacuum at idle while it is warm.

 

i found the problem and it was a simple wire off of a plug..it was barely off so it wasnt anything noticeable (noob mistake)

 

dude i have the same problem!! my car takes forever to turn on and when it does black smog comes out of the exhaust...soo is it a wire off of a plug? and same codes show uppp p0300 and p0301...thanks for any advice u can give me.

 

if you dont get a response danny then make a thread in the troubleshooting section.

Make sure you mention that you have a AP midpipe, AP exhaust, and just changed your coils plugs and wires. Also rebuilt your injectors recently.

 

Well, step # 1 would be to double check all your recent work.
So get under there, and recheck the wires at the plugs and at the coils, and make sure the plugs are properly torqued on the engine.

BC.

 

i mean could it be a bad motor? i know on an old wore out normal motor the oil seals can go bad and then it shoots smoke out of the back.. sounds like bad compression from my point of view(may not be the real answer)