hello first of all i have replaced the spark plugs and leads was running real bad
now what i get is when its in idle about every 10 to 15 seconds i get a little miss when you put your foot down all is good i also replaced the thing that adjusts the idle as it would not idle at all

what next to check i was thinking the fuel injectors
are they easy to get out and how to clean them
does the o2 sensor affect any of this
when i had the mechanic replaced the idle switch he siad somthing about a o ring seal cracked?
this is for my back up car te magna 3l auto
the car has had a big service but due to car sitting for 10 months before i brought it i was told just needed a good run but this problem still happening

i have looked throught the search not much info a lot of people saying clean with wynns spitfire for injectors
i have tried this no go the car has done 228000kms

From what I have seen on here, the fuel additives for injector cleaning are a waste of time and you should look at getting the ultrasonic cleaning of the injectors which will cost alot more but should get a good result. Not sure if that will fix the problem but it is a start. Did the leads and plugs make a difference?

Okay now the car wont be missing if your injectors are dirty, unless completely blocked & if they were it wouldnt be just missing on idle. I actualy started a thread with similar problem, in my case it was MAF sensor, i took it out cleaned it with MAF cleaner & there it was car works normally.

Have you checked dizzy cap and rotor?