2004 RX-8 misfiring

[central]

Recently my 04 RX-8 has been misfiring on the first cylinder when it rains heavey and on startup. Yesterday it started sputtering when I was driving around. Anyone have any idea what is causing this and about how much it may cost to fix? I know nothing about these rotoary engines. Thanks for any input.

 

[SIBalla23]

Does it only do it when it rains or moisture in air? If so, check spark plug wires for damage such as cracks or splits in the wire cover.

 

[central]

I don't drive it every day so i'm not sure if it's only after it rains or not. It is starting to happen more and more. It stopped misfiring after it was driven for a few minutes. now it's starting to sputter during normal driving. The engine light had come on and I took it to autozone and used their diagnostic tool which said it was the first cylinder misfire.

 

[solidtrance]

First of all there are no cylinders on this car unless you have one with a swapped motor.

It could be a lot of things. More details will help use point you in the right direction.

1. How many miles?
2. When was the last time the coils were swapped?
3. When was the last time the plugs were swapped?
4. When was the last time the plug wires were swapped?
5. What was the code that the guys/gal at Autozone pulled?
6. Any mods done to the car?

I would suspect coils/wires/plugs if you go the car used and don't know when they were changed last.

Spark Plugs (30,000 miles)

OEM plugs are recommended unless you are FI, and maybe even then. You will need a 13/16 plug wrench, some extensions and either a universal adapter or wobble extensions to remove and replace the plugs. Be sure to use some anti-seize grease when you install the new plugs.

OEM Leading – NKG PN: RE7C-L
OEM Trailing – NKG PN: RE9B-T

Ignition Coils (30,000 miles)

OEM Coils are recommended unless you can either fabricate a bracket to hold Yukon Style coils or buy a premade kit (such as the one made by BHR). You will need a 10mm socket with a 6 – 10 inch extension to replace them. Additionally you will need to remove the whole intake all the way back to the throttle body.

OEM PN: 18-100B-N3H1-9U, N3H1-18-100B-9U

Plug Wires (30-60,000 miles)

You’re ignition wires should be checked when you replace anything in the ignition system, and replaced when they appear to be worn or the connection with the coil or plug is not very solid. The engine vibrates a lot even under low to medium load. These connections are vital and can cause major problems if they are not solid.

OEM PN: N3H1-18-140B
Magnacor 8mm - W49435
Magnacor 10mm - W45435
Mazdatrix 10-800-Red (Available in Red, Yellow, Blue and Purple)
MSD 8.5mm ??
MSD 10mm ??
Ultra PN: 14R-1003 (good-win), 11516 (racing beat)

All these posts are taken from the RX-8 Basic Maintenance Information (suggested interval) thread (Click to open and read). This thread should get you on a good maintenance scedule for proper RX8 health. Once you have read through the thread feel free to post any additional questions here.

 

[RenesisKing]

Solidtrance hit the nail on the head. I was thinking plugs wires and coils when I saw the title of the thread. There is nothing wrong with the OEM parts if you do not wish to upgrade. The OEM NGK plugs are excellent.