Dealer installed reman engine , coils,wires, plugs....November 2015
Throwing P0302 Dealer tech says it needs new Cat.....1800 dollars later..Installed New Cat converter Dec 2015.

Still thows P0302...Lead tech ohmed out injectors.. he says coils plugs, injectors all checked good, ... Still throwing P0302 at high rpm under load... Tech did compression check... all good...disconnected battery over-night and did 20 brake stomp. No more p0302....

THEN... A week later, throwing p0301.

Dealer lead tech on test drive says it's not really misfiring at high rpms... he says it's running smooth.......says it's "false misfire code." Disconnect battery 24 hours. No more P0301.
THEN...A week later (Yesterday) still trowing P0301. Back at dealer. Tech said it could be computer module.


2006, 79000 mi, Automatic.. everything is stock.

 

Try the 20 brake stomp procedure to clear the NVRAM.

 

Thanks RX8Soldier...forgot to mention that... 20 brake stomp done ( on several occasions) No change.

 

Are you positive that ALL plugs, coils.and wires were verified?

MAF sensor? Fuel pump/ bad fuel?

Was the ess cleaned prior to doing the procedure?

 

Nothing certain on the MAF or ESS clean buddy.
I did see tech pull all plugs & plugs and check them.
If it were a pump or bad gas, would't you feel the misfire at redline ?

 

Maf and ess are simple to do. So make sure you do those (unplug battery and do 20 brake procedure again).

The best way to test the coils/wires is with a spark tester. It's not unheard of for new ones to be bad right from the box.

Bad pump and bad fuel delivery is just that. You need to eliminate the variables in order to diagnose your issue. Don't make assumptions. That could be a fatal flaw...

 

Thanks guys. I'm impressed at the willingness of y'all helping out with invaluable info. I've read both of your post and threads for several hours per day for weeks now. I'm so intimidated by y'alls knowledge that I hesitate to even post my questions. You both have my respect !

But, I guess I'm more confused as to how a major dealership in Dallas wouldn't have said the same things upfront at first. The lead tech is working on it and said he has changed out close to a hundred engines in RX-8's and has never had this problem. He is super friendly and seems to be going the extra mile. I'm trying to be patient and not over step my bounds.
Thanks again.

 

I would swap the ESS and see if that helps. It is the only common thing tied to both front and rear rotor misfires that switch back and forth..

 

I have seen them fail with no code. They just randomly give strange readings.

Since that sensor determines the raw data for both ignition and fuel calculations it is likely the most important sensor the PCM uses

I never let ECU trouble codes (or lack there of) determine a diagnosis when logic says to look someplace

Not saying this is the issue. It could be so many things.

The shielded ESS to PCM wire could be getting random interference from the alternator or power wire as well. It doesnt take much to cause a missfire

 

OLD SCHOOL ???? Did you say old school Charles?
I can top anyone with old school.
I remember school "bomb drills" when we would get under our desk and cover our heads... LOL.

I appreciate all the advice guys.... more than you know.

Paul Osborn

 

I have a 08 Rx8..40th edition...with only 65K miles..and im getting the P0301 code..basically it turns off and on...what i have noticed is that when i rev it a lot...by the next day it goes away...but then when im going up hills after a couple days it turns on again...when i pump good gas..like chevron and shell...it last longer without the light coming on...but when i switch to another gas station like valero...mobil..it comes on even sooner..but my car doesnt get shaky or anything the check engine light is simpy on...lame...but now im over it and i want to truly get that light off...am i doing something wrong or what could it be?

 

It's probably your ignition coils, which have an average life of about 30,000 miles. If you haven't replaced them, do so before they kill your engine.

More info :https://www.rx8club.com/new-member-f...4/#post4533701