I really have no idea... i just dropped a 2007 motor that has 20k into my 2004 rx8 because mazda told me my cat and engine needed replaced...

they wanted 10 grand for everything so i decided to do it on my own with a mechanic and we got everything successfully running but it sounds so wierd... it litteraly sounds like a lawn mower... the car has NO torque and has a really hard time getting up to speeds...

and yes i did put something in place of the cat... there is a straight pipe that was custom made from a shop and they made sure that there are no leaks... but it has no o2 sensor that is supposed to be in the cat.. could this be a problem?

what the hell is going on?

 

injectors,coils,sparkplugs make double sure all are connected the way they are supposed to be. for a 2007 model.
did you have to use a 2007 ecu also?
OD

 

also man look at the 1st thread on this part of the forum--make sure your injectors are like the diagrams listed.
as stated check plugs see how they look.
OD