Raevik

The background:

Me
I know just enough about cars to be dangerous...and am a far cry from a mechanic. I typically use the dealer for repairs, but I'm (long) out of warranty and am interested in doing more work myself.

The Car
'04 RX8 with 68k miles

The Setup
Filled up at a gas station, pulled out and was a bit heavy on it (80% power?). Car stutters HARD, CEL flashes. As I continue to accelerate (to avoid getting creamed), the CEL flashing turns solid and stays on. I stop at an Advance Auto to get the code pulled and it's a P0302 (Cylinder #2 misfire). I chuckle at the irony, then proceed to do research.

What (little) I know/guess:
So a P0302 is a misfire and the typical causes that I turned up from searching here are coils, plugs, wires, and/or fuel pump. Since the fuel pump coming up seems to correlate with low fuel and I just filled that up, I'm tentatively ruling that out.

The most likely cause is therefore plug(s) and/or coil(s). What I don't know is what constitutes "cylinder 2" in the RX8. I'm assuming second rotor? Stupid question...which plugs are those? Is it recommended to do all plugs and coils, or just the ones associated with "cylinder 2"?

Lastly, the CEL is still on. Does this suggest the problem is ongoing, or that the car is simply persistently reporting that the event occurred? Is driving the car in this condition dangerous or otherwise put the vehicle at risk of secondary damage?

Guidance here would be super helpful

Loki

iTrader: (1)

Do all the coils, plugs and wires... soon, don't drive it like this, even at low rpm, you may toast the motor. When was the last time they were changed?
The issue likely hasn't gone away.

Raevik

So I'm unclear on which parts are reasonable-enough replacements.

Advance Auto sells this:
Buy BWD/Intermotor Ignition Coil E1001 at Advance Auto Parts

With people complaining about the quality of the stock coil all over the forums, is a part like this an upgrade, about the same, or worse than OEM?

Also, AA sells these plugs:

Spark Plugs for Mazda Rx-8 (2004, 2005) - Advance Auto Parts

Are the "hot plugs" the RE6C-L ones recommended over the RE7C-L? This was part of the steps to address flooding and cold starts, right?


I'd consider avoid buying retail aftermarket parts and getting OEM online, but with advice like: "don't drive it like this even at low RPM", that tells me I need to get this fixed urgently. This is a daily driver vehicle...

Thanks.

tza0001

iTrader: (2)

Raevik with over 300 posts I would expect you know more about plugs, coils, and wires....Plugs you should use the OEM ones (NGK iridium). As far as coils and wires there are some options other than OEM. Look at BHR kit if you want to upgrade. If not just use the OEM ones and make sure you change your ignition every 25k to 30k miles. Here is some more info on coils: https://www.rx8club.com/tech-garage-...-coils-210238/

Raevik

Couldn't resist taking the shot huh? Owned the car for 9 years, but I clearly opened with "not a mechanic" and "have used dealer for service in the past". I thought that would paint the picture clearly enough...but apparently not.

Thanks for the link. It looks like a post in there spotted the same OES coil parts I was interested in and is asserting they are actually the same physical part. I'll give them a shot.

On the topic of hot vs "standard" plugs, working through this thread https://www.rx8club.com/tech-garage-...-plugs-129479/

tza0001

iTrader: (2)

^I was not trying to be offensive. Just wandered...Apologies if you thought my comment was offensive or inappropriate.

Raevik

I appreciate that.


So, the PLOT THICKENS:

I installed 4 new plugs and 4 new coils today. The car fired right up with no issues (hooray!). I took it for a spin to see if I could recreate the original problem (heavy load + >7krpm = CEL P0302). Sadly, I did.

Sequence of events:

-Warmed up car, took it out onto a major street

-Gunned it a few times winding out the RPMs. It sounded good and pulled (mostly) as hard as I wanted

-Stopped and filled up gas and reset the ECM using the brake method(I figured it might have retarded timing or otherwise made adjustments due to the misfire?)

-I pulled out of the station and got on it again. This time, it hesitated hard above 7kRPM and the CEL came on flashing, then stayed on....identical to the first time



So the only thing I didn't replace was the spark plug wires. I'm not positive, but they might be original (9 years old). I guess that's the next step? Any other suggestions?

Strange coincidence about the gas station fill-ups right before each incident. Any way the fuel pump could cause the issue when the tank isn't low?

dannobre

iTrader: (3)

Did you check the ESS sensor?

If the wires are 9 years old they are due for a change

Bladecutter

Yup, replace the spark plug wires, and if it is still flashing after that, go get a compression test done, as the problem in most likely internal to the rear rotor.

The only other thing to check is if there is now a new/different CEL code.

BC.