Mazda Demio DY coil packs .

Has anybody had to replace one or more of these,what are the symptoms? I,ve got one that starts ok but after running and driving for a bit when started again has a "miss'which after a while seems to go away Any help or advice would be appreciated .

ok a few facts coil bapacks dont work right then not right and then right again. a coil pack is made from wiring wound round and round its either broken or not. or, its braking down with heat but that means its not going to be fixed when hot the hotter the more things expand like the faulty wiring , so for that reason you cant rule it out 100% because you need to actaurly test it , but it puts it in the verry unlikely basket of problems .
, if i had to ask my cristal ball then it could be a head gasket problem because the cooling system gets pressurised hot so water would enter the cilinder when you shut it down and then that cilinder wont fire for a while with the sparkplug getting wet and once its dry the combustion is greater then the pressure from the cooling system.
So i would check if you have still got enough cooling water in the system
Never open a hot system. I dont know how mutch you know .
But that would be the first thing to check from your limmited information you have given to make a possible reason. there will be plenty more reasons this is based only on what you wrote.

if plugs are old change them ! take for drive when cool enuf remove all plugs in inspect . all should look same ? if one blacker ,wetter than the rest clean and swap that plug for another and also coil pack swap that to another taking note where u swaped to ! take for drive shut down in take for another drive when occur again pull plugs in check . if it same pot could be coil lead if its the one u swap coil pack too or plug too .

The car starts as good as gold and runs well for a few days then after running around develops a :miss: not a bad one just a bit lumpy at idle which clears when given a bit of throttle.Motors was washed down(not by me) and i suspect bit of water in wrong place.Do the coil packs connect to a distributor.Plugs were supposedly changed but from appearances doesnt look like it to me.Looks like a bit of an exercise to get at spark plugs but might try there.Definitely not a head gasket though, Is there 1coil pack for each plug connecting to a distributor or what Ta

Lol you don't have coil packs AND distributors, the point of having a coil for each plug is that you dont need a distributor and parts that wear out and the associated timing inaccuracies and loss of spark energy. Yes it would be a good idea to check for water down the plug holes and for any 'tracking' down the spark plugs themselves, get the plugs out and look for dark stain lines down the porcelain.

Thanks,will give it a new set of plugs and have a good around when i have all the plastic crap of the motor Cheers .

I would disagree with you regarding that point. As any A32 Nissan Maxima owner that has had to replace a coil pack will tell you, that's exactly what happens, and they are well known for it. Starts as an occasional intermittent miss, sometimes when cold, sometimes when hot. Occasionally It will just start missing at low idle (in D, foot on brake and A/c going) but not always a continuous miss, and sometimes when hot or cold it will miss continuously on startup, but turn it off and will start straight away perfectly. So far I have replaced 3 coilpacks in the 4 years I have owned it, and always the same symptoms as described above.

Edited to add. I have never had one just stop working permanently so the engine misses continuously, its always been intermittent.