Hi guys new to this so sorry if this is posted in the wrong place.

I have a 2015 mk3.5 focus st3 which I bought just before Christmas and it's been mega I absolutely love it but about a week ago I noticed it started to stutter at random intervals and it's very intermittent.

It seems to do it most under firm acceleration when the boost pressure gauge is at about .5, it feels like the fuel gets cut for a second and then it carries on as normal. And it seems to be doing  it a bit more regular as time goes on. No error codes have been logged.

I'm going to ring my local deal this weekend, but thought I would ask here first to see if anyone has any idea of what it could be?

Strange you should mention this.

I PX'ed my 2015 ST last year and the new owner tracked me down.

He stated that he was getting the same trouble as you are having and apparently Ford informed him that this was a known issue and a engine map update was available to sort this out.

Must admit I never had this when I owned the car but then I did have a Bluefin map running on it which negated  the map glitch anyway.

I recommend you go to a dealership and enquire about the update.

You may also want to consider running the car on higher octane fuel as the ST does run smoother on it, I always use Tesco Momentum 99 and although it is a few pence dearer per litre you will feel the benefits.

Thanks for your reply I'll contact the dealer and have a word with them and I thought it mite of been some bad fuel from shell but I've refilled a few times now and it' still going on. I normally do fill up on the higher octane fuel anyway.

4 hours ago, Stoney871 said:

Strange you should mention this.

I PX'ed my 2015 ST last year and the new owner tracked me down.

He stated that he was getting the same trouble as you are having and apparently Ford informed him that this was a known issue and a engine map update was available to sort this out.

Must admit I never had this when I owned the car but then I did have a Bluefin map running on it which negated  the map glitch anyway.

I recommend you go to a dealership and enquire about the update.

You may also want to consider running the car on higher octane fuel as the ST does run smoother on it, I always use Tesco Momentum 99 and although it is a few pence dearer per litre you will feel the benefits.