On my '04 MT with a intake and catless ext w/no muffler i was getting the missfire code after about 400 miles, it would throw the code in 2nd and 3rd around 7.5k. i did the e-senser reset and drove and that didnt work so i cleaned the e-sen. and that didnt work so did the e-sen reset and drove and agian it missfired.. in the end the fix was the room fuse pull. hope this helps overs

 

I am not quit sure wat u mean "the room fuse pull"....I am a new to the Mazda world. So could you explain wat I should do, cuz I have got the same code on my RX-8

 

In the footwell is a small fusebox - one of the fuses is marked 'room', it actually controls the computers memory along with the interior lights.

Best fix for a misfire code is new plugs. 90% this is the cause of a misfire at high revs.
If that doesn't work, new coils or use higher octane gas.

S

 

Thx for info...I replaced the plugs which needed it but found out that a coil was bad...that code scanner has already paid for itself...lol

 

Having hte same problem, I replaced the plugs but didnt do the trick. I'm assuming its the coils or wires. Just curious for anyone out there tho, might be a dumb question, P0302 is a misfire on the 2nd rotor, so if I switch the coils around with the 1st, will I get the P0301 code?
Gonna test it out soon...

 

besides switching the coils, and then switching the plugs does anyone have any ideas for this? i have tried switching coils then switching plugs and my misfire stays on rotor 2 (p0302). i actually had my coils plugs and wires replaced 2000 miles ago while a new engine core was installed under warranty. I was wondering if it might be a grounding issue? where does the ignition system ground?

 

Look for a intake leak. clean the MAF

 

cleaned intake, throttle body and maf last week to no avail. any other ideas?

 

Try testing out your SSV.

 

Access Port.

Tune from factory is too rich which cause misfires.

Can not get rid of misfires unless you get Access Port.

 

just a few weeks ago i tested the ssv to be ok and functional, there wasnt an issue like i had seen others having where the ssv was sticking and oil was coming into the intake etc etc.

there has to be something w/o getting accessport to fix this. on my previous engine this never ever happened up until the day it blew at 55k. does anyone have a reference that can point out where the ignition system grounds i would really like to check any and all grounding points for solid connectivity.

thanks again everyone for the help!!!

 

This doesn't sound like something that is related to the SSV (unless it was stuck open).
But you would also get a code for that too... but you're saying that you ONLY get a P0302, right?

I read that you switched the coils and plugs from one rotor to the other.
Did you also try switching the plug wires from one to the other too?

Are you running an aftermarket intake setup?
If so what kind?
Have you checked for any vacuum leaks in the intake setup?

You may need to get a compression test done if nothing else is noticeable.

 

So your running a straight pipe and expect to get rid of misfires? It ain't gonna happen.

Your 1st post says no cat no muffler.

Get an Access Port.

The car was not designed the way you have it. No CAT is illegal.

 

all that is on the car is hks intake and hks exhaust. the cat is stock. (not my post about not having a cat... i totally hijacked this thread haha) ill switch the wires to see if that changes anything but i doubt it will... anything else?... and does anyone know where the ignition system is grounded?

 

not having a cat isnt illegal everywhere or for everyone. I have no cat and am perfectly legal with a transporter tag

the ignition system grounds on the plate bracket the coils mount to. Grounded straight to the block.

sounds like you might have either fuel/air delivery issue or a tuning issue. If the car is too rich or too lean then it will misfire.

If you have a leaky injector or a vaccum leak this will cause either. or if the pcm flash is not calibrated right it will not be tuned for the right AFR and not spark at the right time.

Also try reading the EPS with an ohmeter or something to see if its good while cranking

 

I have the same code come up today. (just had new spark plugs put in too) What is the room fuse pull and how do I go about fixing it? I was going to take it to the dealer but I am afraid they will charge me way too much to fix it.

 

do you feel lack of power?

 

Yes there is a little lack of power and a slite missfire. I had a friend that is a mechanic check it out for me and he said it needs an air fuel meter. Judging from all the threads I have read I thought it may be coils. He said that he could not check the coils until after that air fuel meter was installed. I forgot to add that I also had a code POO37.

 

drove my car yesterday and my engine light came on. checked for codes, i got codes p0302 and p2259, from what i gather on the p2259 i need to test the air solonoid, for the p0302 i changed plugs and wires less then 5,000 miles ago.

so next i should test coils? what is fuse pull? its only for the guy running no cat right? or no? also what is ssv and access port?

 

ha found my damn missfire problem, went to take out the air solonoid to test it, looked down and found one of my new spark plug wires chewed up, ****** rats got in engine area and chewed through my damn wires, *******, simple fix tho, soak rag with rodent repellent, keep in engine bay, will keep the ******* away.

 

I had the same problem with my rx-8. po302 code coming up. I also changed the plugs, and spark plug wires and the coils. and the code still came up. I was having a hard time starting in the mornings and the car would run rough at idle. I finally found the problem, #2 rotor injectors were having leak down when I would shut the car off over night. the #2 rotor would get flooded, so basically you have to rebuild or replace the #2 injectors. there is one primary and two secondary's. the primary is brown and the secondary's are yellow. this problem will constantly keep coming up if you don't change injectors.

 

Interesting. Thanks.
Actually I have heard very little about issues with the injectors so this is good to know.

But you did just bump a 5 year old thread.

Oh and the injectors are different depending on the model.

 

I seen it couple of times, replace/clean, everything good again

 

I had this problem start yesterday actually and only have the P0302 issue. The car hard started but I had not started it in 10 days and it had been sitting in a hot garage since the last I drove it. Not sure if that caused any issue (when someone said that they had a leak down causing a rotor 2 flood while sitting). Got it again this morning when I started the car before driving it.

I am new to the car, bought it with 81K on it and I now have 82500 on it. But right before buying it the prior owner had ran BG 44k, seafoam, new starter, new plugs, new coils, and new wires. All at around 80K miles. So these are only 2500 miles old. I would hope that they havent gone bad that quickly. I am using premium fuel.

 

Tried all the above with limited success. Found that the HT leads to back rotor would occasionally short out against the block ( near the dip stick mount ). Tying the leads back with cable ties solved my P0302.