Rapid studdering 3rd gear through to 6th

[Jaymac]

Hey all first post here,

Recently purchased a 2016 mk7 st-3 fiesta running puma speed stage 2, I noticed a problem when you put foot to the floor in 4th 5th and 6th the car shudders and misfires in quite a rapid succession.

Immediately I assumed spark plugs so got them changed but problem still persists no engine management light is present the blow out valve changes its tone to a slightly more high pitched noise when it shudders but I'd assume that's normal in higher gears.

I can still floor it to a certain point but there's a point where it will struggle to keep pushing.

All help appreciated

Note not sure if coil pack or wiring triggers engine management as they are the individual coils.

 

[TyphoonFiST]

How many miles/KM on the FiST? Stock Turbo? If yes return it back to the stock tune to see if it still persists. It might be the tune. I know your FiST is MAF based Vs. Map tuned also.

 

[Jaymac]

Just turned 80k miles, and yeah still stock turbo

 

[TyphoonFiST]

Just turned 80k miles, and yeah still stock turbo

Return to the Stock tune if possible and see if the shuddering goes away. Report back with findings.

 

[Jaymac]

Thanks will do!

 

[FieSTa Blanca]

Bad injector(s) maybe?

 

[Lays]

Don't floor it in 4th below 3000 RPM, and don't floor it in 5th or 6th unless you're doing a pull from a lower gear first, low RPM + high gear is terrible for these engines. Easy way to blow them up. (Low speed pre ignition)

I'd check coil packs and injectors next, and maybe tighten your plug gap.

 

[FJ16]

Sounds like coil pack to me (from past car experience, haven't had this issue on a Fist in particular).

 

[TyphoonFiST]

I cant say this enough...Ign. Coils break down over time/usage. Should be replaced every 50-75k as a maintenance item. just like O2 sensors every 75k.