New to all of this.
LOVE the RX-8 but can't decide if she's an angel.... or the devil in disguise.
Paul

 

Hello Paul

To answer your question, misfire is usually coils plugs and wires. You mentioned that it had new coils plugs and cat. What can happen in these motors is the ignition components wear out, and then you get incomplete combustion. This clogs the cat, which leads to back pressure (the engine really really doesn't want back pressure) and it all goes downhill after that.

It sounds like this car had some issues in the past, if those things have been replaced. You want to make sure the ignition system is still in good shape. Coils can overheat, wires can fail, etc. OEM parts are always your best bet. I would try changing the plugs front to back, see if the problem stays on rotor 2. Friendly warning, do not change plugs top to bottom. The rotary engine uses two spark plugs per combustion chamber, leading and trailing. They are not interchangeable. Only change plugs front to back. Then change the coils. This is the only way to do it....methodically step by step.

 

Welcome aboard. Everything you ever wanted to know about your RX-8 is on this site and probably stuff you didn't want to know too. Ask away all the questions you have in mind!

 

Thanks for the info Chris.
In the last 8 weeks, Dealership put in new engine (actually 2 new engines...1st new engine turned out to be bad from factory with low compression), Cat converter, coils,wires, plugs.... Compression checked good. Lead tech ohmed out injectors... Still throwing P0302 at high rpm under load... He said he has never seen this before...Still at dealership.

 

DOA remans are rare but not unheard of. audiodallas, search here for the NVRAM reset procedure. Anytime you install a new engine this should be done or you will get misfire codes from not resetting the ESS profile.

 

Thanks so much 9krpmrx8... wow... Tech didn't do a brake pedal reset. Unless there is another way that he could've reset it... maybe his computer through odb2 port?

 

I am sure the Mazda WDS could do it as well. But it takes two seconds, worth a try. It fixed a misfire code I was having after an engine install, that is how I learned about it.

 

Dealership lead tech reset NVRAM , Still threw P0302 at red line under load .
Escalated up to Texas Regional "Mazda Tech Specialist" who told him to disconnect the negative side battery terminal and let it set overnight. This morning he reconnected negative cable, road test...red lined several times. No CEL !!!!
Hallelujah !

 

Dealership lead tech reset NVRAM , Still threw P0302 at red line under load .
Escalated up to Texas Regional "Mazda Tech Specialist" who told him to disconnect the negative side battery terminal and let it set overnight. This morning he reconnected negative cable, road test...red lined several times. No CEL !!!!
Hallelujah !

 

Tech disconnected battery over night. Next day.... no CEL.

 

BTW .... quick question.... why do they want us to call them tech instead of mechanic ?

 

Because it sounds fancier.

I'm not a sales rep, I'm a brand ambassador! I'm not a garbage man, I'm a waste and recycling engineer!

 

I think of mechanics as people who mostly do physical labor (swinging wrenches, etc) I think of technicians as people who do what a mechanic does, BUT also use fancy computers, and really know their stuff.