Flat spot on 2005 Focus ST

[Simon Bags]

Morning everyone. Got a bit of a problem with the ST. 55 plate, 34k miles. Starting to develop a flat spot after engaging 2nd gear and giving it some acceleration. It's not doing it all the time and it doesn't last for long but it's starting to really annoy me.

It's got the Mountune conversion.

Also, and I'm not sure if this is related or not, but I'm also suffering with quite bad tram-lining. Perhaps they are related? Thinking maybe drive shafts?

Car going into a friends Garage this morning so hopefully nothing too serious but it's more a case of hoping he does actually find something.

Thanks for reading.

Bags.

[Justin S]

The Mountune fits the K&N panel filter which can cover the air flow meter in oil and cause stalling. As for tramlining, what tyres are on the car?

[Simon Bags]

Justin S said:

The Mountune fits the K&N panel filter which can cover the air flow meter in oil and cause stalling. As for tramlining, what tyres are on the car?

Morning Justin, thanks for the headup on the K&N, will investigate. However, after the 2nd fill up after using Wynn's Injector Cleaner, it does seem to be slowly getting better, I think.

Cheers, Bags.

[Justin S]

Simon, have you got the 57i K&N kit or just the panel filter? The 57i is known for causing low speed hiccups due to turbulence in the airbox causing an airflow issue. But when it overcomes that, boy it does go. I know from experience on this.I would have thought it unusual on an injector fault, as they are pretty good. Might be worth getting it checked for codes etc.

[Simon Bags]

Justin S said:

Simon, have you got the 57i K&N kit or just the panel filter? The 57i is known for causing low speed hiccups due to turbulence in the airbox causing an airflow issue. But when it overcomes that, boy it does go. I know from experience on this.I would have thought it unusual on an injector fault, as they are pretty good. Might be worth getting it checked for codes etc.

Morning Justin, I believe it's just the standard K&N filter, replacing the original Ford type when the Mountune was installed/fitted etc.

I think I might have a quick look see in the filter housing soon, see if anything obvious?

Simon.

[Justin S]

When were the plugs changed? When mine were replaced it weirdly made them a lot smoother. Dont know if the Mountune may cause the plugs to run hotter or wear a bit quicker? Other than that, although it may come up with a fault code, maybe a coil pack breaking down?