So I just bought a 2006 mk6 fiesta zetec s, and it feels like it may be running a little rougher than usual, I've many opinions and 99% of them had said get a cold air intake. Now I'm bit of an amateur when it comes to upgrades and modifications, but does anyone know of any realiable kits that won't break the bank? 

Thanks 

*open to alternate suggestions*

First job - full service. all fluids, plugs, filters etc. - also if the previous owner was running an oiled panel filter / cone - it might have clogged the Mass Air Flow sensor up - had this trouble myself, a quick spray of contact cleaner and all was well.

If its still running rough check the leads and coil pack (these have both)

A cold air intake wont make much difference (if any) to your current set up and wont fix the issue of rougher running.

If its still running rough after the above, come back and let us know and we can try and help where we can, or, visit a local trusted mechanic to have a look at things for you.

 

is it petrol or diesel?   and when is it rough?  cold start tickover ?    on tickover all the time even when hot?  on acceleration?   on steady speed along main road?

I agree with Tomson on what he says about cold air intake

He replaced the plugs, so I'm presuming it's a petrol. No MAF, it has a MAP sensor. New leads may well help as the old ones are over a decade old.

I can't see where it says he replaced the plugs. it says 

"So I just bought a 2006 mk6 fiesta zetec s, and it feels like it may be running a little rougher than usual, I've many opinions and 99% of them had said get a cold air intake. Now I'm bit of an amateur when it comes to upgrades and modifications, but does anyone know of any realiable kits that won't break the bank? 

Thanks 

*open to alternate suggestions*"

Sorry, was on a small screen, misread the 2nd post as part of the first.

The car shouldn't run rough using the stock airbox so something else must be to blame.

It's always worth cleaning the MAF/MAP sensor as they can get contaminated over time. This can cause a rough idle and jerky throttle response.