Possible missfire

[scrim]

Hi all I have a saxo 1.1 2000 I have changed everything on the ignition side and also cleaned the crank sensor but it still idles up and down a bit and sumtimes when u listen at the back it will have the occasional pop what else can cause this cheers

[badboyracergt5]

idle sensor or timing could be out

[scrim]

Icv is new and timing is spot on

[badboyracergt5]

injector cleaner and check your air intake

[badboyracergt5]

clean your sensors too

[lilwayne]

is it when driving or just idling ?

[Mark51]

have you checked the plugs?

[badboyracergt5]

other thing is the coilpack it happened to my brothers car

[scrim]

coil pack is new, along with plugs and leads, its only when idle really, but when driving if i take it over 4k revs it sounds really rough but under its fine, i cheked my plugs the other day and all are nice and grey which is a good sign, could the cat cause problems like this? cause i know my cat is fooked im in need of a new one

[badboyracergt5]

the cat could be blocking i had that problem when some t**t drove in to the back of me an broke my exhaust and cat

[scrim]

will have to see what its like when get a new cat

[dima]

it might be your lambda sensor. just disconnect it, and see how it runs, in worse case do a diagnostic test in any garage, its like £45 but u will know for sure what is wrong with it.
gd luck