Flashing CEL... that goes away?
 

So, after having a pretty rough misfire situation 4 days ago I have replaced:

Coil Packs
Plug Wires
Spark Plugs
Catalytic Converter (under warranty, thank christ.)

Got the car back from Mazda and everything was pretty fine. But I've been having this recurring problem that I just can't seem to pin down.

If I gun the engine hard, at around 4-4500rpm I get a flashing CEL. If I back off immediately to 3-3500rpm it'll flash for another 10 seconds and then go out. If I keep pushing it (to run it hard to clean out the carbon) it'll flash for a little longer and then stay illuminated.

Running a reader puts it as a P0301 (Cylinder #1 Misfire Detected) which is odd as the car is running smoother than a baby's bottom wrapped in a silk cloth. I'm currently running a bottle of injector cleaner with a full tank of gas to see if that may be the issue - but are there any other suggestions?

(Wow, I've been lurking for a while. Can't believe this is my actual first post.)

Need to make sure the coils, wires, and plugs are all connected snugly. If they are, it may be an issue with the PCM or maybe the Eccentric shaft sensor. Those are the 2 likely causes, I would start with the ESS.

^^ +1
double check all the connections relating to the ignition.
make sure the wires are properly secured on the coils and make sure they're on snug at the spark plug. (they sometimes come loose)

Also, double check to make sure they're going to the proper plugs. Could have gotten swapped around on accident.

we need to make the Search button flash ...

lol

Excellant idea!

Try re-setting the ECU and cleaning the MAF.

My apologies mate, I simply threw it up quickly this morning before I took off before work. I'll make double sure not to offend your delicate sensibilities whenever I post from here on out, 'kay? :Peace:

I'm pretty damned sure it's not the Cables as we checked 'em thrice before leaving the workshop, but there's no harm in trying a fourth. I'll definitely check the ESS in the morning though - would be super nice if it's simply a loose connector.

Many thanks for the suggestions, will post again tomorrow to update.

Well, thanks for all the info - seems to still persist, sadly.

ESS is fine, checked the connection - no burning or charring and it fits quite snugly. Quadruple-checked the connections from Coil-Wire-Plug, everything's kosher on that end as well.

I have noticed, however, that the 20-brake-pump doesn't clear the CEL, only using a Code Reader seems to clear it out. Does that perhaps point to the PCM? Time for a re-flash?

If the code is still coming back, use have an issue somewhere in the ignition system. Have you pulled the plugs on the front rotor and taken a look at those. Atleast with the code you keep getting, you have place to start. Those coils on the front rotor may be bad also, you check them with a ohm meter.

I replaced all 4 Coil Packs, all 4 Spark Plugs and all 4 Plug Wires a little less than a week ago - so I would certainly hope that they're not the problem, but stranger things have happened. I'll make them my next stop.

I really wish I had a garage to work in. Stupid apartment complex. D=

Might be a stupid question but are the T and L spark plugs in the right holes?

Also, you could have gotten faulty coils or spark plugs. Just because they are new doesn't mean they work. Gotta love the QC now a days

Perhaps a dumb question... but did you have this problem before swapping out the coils, plugs and wires?

I had a genuine misfire in Rotor 2 - it simply wasn't firing at all. Made for a scary drive home after it happened.

The CEL's before the replacement was for a P0037 (Rear O2 Sensor) and P0302 (2nd Rotor Misfire). I replaced the O2 Sensor and all 4 Sparkplugs at that point. Didn't fix the problem so I got it looked at by the crew down at Mazcare.

All 4 coil packs had a little white burn on the underside and one of the coil wires on the 2nd rotor wasn't connecting properly, there was green discoloration on the end of the spark plug where it was slipping.

Took it into the shop and replaced the whole lot as a precaution (4 Packs, 4 Wires) including getting the Cat replaced at the dealership. Now the car seems to be driving just fine - but getting the CEL unnerves me something horrible.

After spending nearly $800 I didn't have on getting it fixed, I really can't afford for too much more to be wrong (silly as that may sound).

I'm about to go out and pop the hood and check the connections one more time. If that doesn't do it... I dunno, to be honest. =\

Just got done out in the parking lot - everything is tighter than a nun's nasty.

At this point my next step will be to check the coil packs as jmc suggested.

I've searched the forum thoroughly, and I'm guessing that must be it - everyone else who presented with the same symptoms as myself managed to get it to go away with replacing the parts, so maybe a faulty part is what's causing it?

Augh.

I'm not willing to say I've fixed it just yet - need to wait until I go to work tonight to give 'er a bootful up to 9k RPM to clear it out - but I think simply removing the negative battery terminal for an hour and putting it back might have done it. Drove to pick up the fiancée today and had it up in the 4.5-5.5k range and no flashing light, which is a marked improvement.

Will report back from work. Here's hoping.

Reset the fuel trims. . . those would have to be all sorts of messed up to cause a misfire... but its possible that it would adjust to the new coils and stronger spark.

Well, I think I'm ready to call it.

Driving to work this evening, pulled out onto the 400-N onramp. Held a steady 6.5k RPM for 30 seconds or so while waiting to get out from behind another car, then gave her the spurs and ran until I hit Missile-Lock. :naughty:

No kicks, no splutters, no loss of power and most importantly - no CEL. Just the wonderful responsiveness that made me fall in love with this car in the first place.

Many thanks to you all for your help and suggestions - you've saved me a lot of money that would've otherwise been wasted.

Good to hear you figured it out. Wonder why the trims were so fucked up?

same thing happened to me, my car was chocking the last time i was driving it, and since my car has been in a body shop, so i pour a fuel system cleanser with my new gas.
my car still does the same thing (chocking) and misfiring with CEL flashing and stayed on.
so i changed the coils the next day, and it is still doing it (chocking) and CEL flashing but didn't stay on.
would it be the fuel system cleanser??

got mine fixed by resetting the eccentric shaft sensor!!
yea ya!

ya make sure, everything is installed properly

I've got a similar issue with mine after installing the AP pulley. Going out to try and reset the ecu again now.