linck32

hello people.

so to make it short, i bought my 04 rx8 about 2 months ago, and after few weeks i noticed that my car had a misfire, i took it to the dealership and they replaced the plugs and the wires, but after another few weeks the problem came back and i decided to change the coils, sadly the problem did not went away, any suggestions??

thanks.

VOODOO8

Assume you have a CEL that goes along with that misfire - either actual or at least pending.

What is the reported code?

If you don't have access to a CAN protocol capable scanner, hit Autozone or similar for a free read.

linck32

it appears po302 and sometimes po301, and the misfire usually happen between 6000 and 8000 rpm

Mazurfer

You need coils!
They replaced the plugs and wires, but you need coils.
Do some searches on here and you will find where to buy them and how to install them. It's pretty easy.
If you go to the dealer they will rape you to the tune of about $300.00-400.00

linck32

nop, i already replace the coils and i still have the problems, i replaced them about a week ago

VOODOO8

Got 1st base covered with coils, plugs, wires replaced so its on to 2nd base.

If your only pulling misfire CELs at higher RPMs (with a flashing CEL indicator light to go with them I assume), then next few things to look into would include:
* check for tightness of fit of the wires to both coils and plugs.
* swap wires with known good ones, one of them may have been damaged during install.
* Remove and clean MAF with MAF cleaner (gently please).

peterlemonjello

This is a crap shoot but check the cat.

linck32

ill do that this weekend and tell you how it goes, hopefully it works, and about the cat, i hope is not the problem cos that thing is too expensive :s

Mazurfer

Sorry, I missed the coil statement you made in the original post. Having said that, it is still possible for a new coil to go bad. Some have been bad right out of the box.
Also, check to make sure the plug wires are on tight...........on both ends. There is a tendency for one of the front ones to work loose.
Why that one, I'll never know.

MariesRX8

Worn out engine mounts? I dunno if it's true, but some people have suggested that the vibration might cause misfires.

Mazurfer

I'll go along with that as a possibility. I have heard of it as well, but haven't experienced it.
If I had a really rough vibrating idle, I guess I would look into it.

RotaryRacer03

Im having the same problems with my 04 AT GT but am also throwing a P0410 air injection system fault. i havent replaced the coils yet and the plugs are about a year old i can start by checking the wires for tightness and ceaning my MAF but is there a way to test my coil before replacing it?

Any suggestions about the P0410?

Mazurfer

Ignition coils inspection pdf is attached.

In terms of the P0410, that is most likely the air pump.
Only need the air pump for emissions at cold start and comes on for only about 20 seconds.
You can just unplug the air pump, but.............since you are having other issues, I would want to make sure your CAT isn't clogged.
Better take the CAT loose at the front, move it to the side and peer in with a flashlight and see if honeycomb is intact.
FYI................weak coils can cause unburnt fuel dumpage into the CAT where it may ignite and/or just break up the honeycomb........leading to clogging.

RotaryRacer03

ok thanks for the help i cleaned the MAF and checked my wires for tightness, the trailing were good and tight but both leading wires were kinda loose. i did the spark test as it said to on the attached pdf but i dont have access to a timing at the moment to do the full test. but i did get spark from all 4 coils/ wires/ plugs not all were the strong blue spark like they shold be though whitch probably means the coils are weak and not providing enough spark to ignite all the fuel right?

As far as the CAT goes i havent had a chance to jack it up and get under it to check but if it is clogged whitch i have a strong feeling that it is whats the best way to go about fixing it, repalce it with a new or aftermarket one or a test pipe? or maybe hollow it out?

Thanks again for any help

WingleBeast

most likely the cat, your misfires will start to creep into lower and lower RPMs untill the car in undrivable. Midpipe it.

RotaryRacer03

your right its already crept down to 4500 RPM. wheres the best/ cheapest place to get one?

voodoo11b

im having the same issue with my 04 MT replaced plugs,wires coils still getting misfire codeP0302 maybe i should swap exhuasts and cats