Occasionally misfire only on start up

[Dazza44]

Hi everyone,
As above really sometimes on start up(only when car is cold) I have a wat sounds like a slight misfire(no flashing cel) or anything it just appears to struggle to rev this last no more than 30 seconds then all is good never happens any other times and only every now and again
Mazda rev c coils 9k ago
Magnecor leads
Sparks 8k
Any ideas much appreciated
Dazzq

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[Paul_13]

I get the same issue. I'm guessing it's from where the ECU is injecting more fuel to compensate for the cold start and the engine struggles to burn some of it off. Or tired injectors?

I also get a massive misfire symptom when i accidentally turn the engine off cold and start it again. completely drops on one side of the rotors for about 5 seconds. nearly dies but catches itself and smooths out. I'm pretty sure i flooded it!

[Dazza44]

Hmmm,it's odd as I mentioned it doesn't allways do it even from.cold just occasional on 10 cold starts it may do it 2 or 3 times.
Car runs perfect otherwise
I have done the reset just in case but that changed nothing

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[acegeezer]

Throttle body?

[Dazza44]

How would.i inspect that John or how could I tell of that's the problem.

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[acegeezer]

Pete told me mine was that and it was let it tick over for about 20 minutes without touching the throttle, maybe something else but that needs an expert opinion maybe.

[kopite72]

What's the story with the CAT?

[Ainmhidh]

[jamiegosling]

Mine does this as well, although not so much if its cold but if it hasn't been started for a week or so. Again, no engine light and clears up after about 30 seconds. Got RRP mk2 coils, and a high flow cat. I wondered if it could be some kind leaking seal letting water into the rotors, although the coolant doesn't seem to be going down.

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[Dazza44]

Has no cat

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[warpc0il]

Has no cat

[Dazza44]

Any other thoughts/ideas for me to check ?

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[warpc0il]

How long since you did a full battery disconnect and 20 stump reset, from cold?
Sometimes the "learning" process can be corrupted by unusual conditions and reset does the trick.
https://www.rx8ownersclub.co.uk/forum/v ... 25&t=34703

[13Black]

youtube

That guy was in the audience of a comedy club in London a year or so ago and was certainly looking a little worse for wear and um, not as well-spoken though, the lady he was with seemed a little more of a handful.