Engine jerking/stuttering under acceleration

Ford Puma ST Chat
Fberlo
Posts: 5
Joined: Tue Apr 02, 2024 9:27 am

Post by Fberlo »

Thanks everyone.
Just asked my local ford mechanic to change the plugs next week. Will also ask him to run a diag while at it.

Fberlo
Posts: 5
Joined: Tue Apr 02, 2024 9:27 am

Post by Fberlo »

Sparks wrote: Tue Apr 02, 2024 1:00 pm
Fberlo wrote: Tue Apr 02, 2024 9:43 am Hello all,

I have bought a used Puma ST from 2021, with 13k miles on the clock. Recently, the car has been stuttering/jerking under acceleration (heavy or light load, at highway cruising speed, happening once every 100-200 miles I would say, very randomly). Two-cylinder in eco/normal mode sometimes (3 times over 1000 miles) doesn't switch to 3 cylinder mode unless I downshift, but works normally otherwise.
No engine light or anything.
Cars runs great otherwise.
Maintenance with Oil change has been done twice since bought new, but owner's mechanic did not seem to change anything else other than that.

Question:
- could it be related to the sparkplugs? And Wouldn't I receive an EML in this case?
- Can't I just wait the next oil change next year to replace them?

I feel it's a bit unnecessary for it to go under maintenance once again, and changing plugs under 20k miles seems a bit hasty...

I would be very gratefull if anyone could advise me on this! Thanks !
Hi welcome to the forum. Where are you located?
Possible some dirty fuel has got into the tank.
I would say it's worth having it checked out.
Hi!
I'm located in France. It's been occurring on both 98 and 95 octane fuel types.
User avatar
Ron240
Posts: 770
Joined: Sat Jul 01, 2023 6:01 pm
Location: Fife

Post by Ron240 »

Reading through this thread regarding spark plugs...and my personal opinion is that it is ridiculous to change spark plugs every 12 months/12500 miles. I could understand it if it was an exotic car in a high state of tune...but its just a run of the mill Ford.
My car will have covered less than 3000 miles at 1 year old and I will be amazed if they routinely change the plugs.
2023 Puma ST (1.5 200PS), Desert Island Blue with Driver Assistance Pack.
matthen
Posts: 142
Joined: Mon Dec 20, 2021 3:23 pm

Post by matthen »

Ron240 wrote: Wed Apr 03, 2024 12:21 am Reading through this thread regarding spark plugs...and my personal opinion is that it is ridiculous to change spark plugs every 12 months/12500 miles. I could understand it if it was an exotic car in a high state of tune...but its just a run of the mill Ford.
My car will have covered less than 3000 miles at 1 year old and I will be amazed if they routinely change the plugs.
It’s a 3 pot producing 200 BHP, complying with all sorts of emissions limits - I’d say that’s a fairly high state of tune 🙂

OP: how'd you know when it's in 2 cylinder mode? I've done 25K mi in mine, a good portion of them motorway, and I'd confidently say it has never deactivated a cylinder.
Puma ST (Performance Pack) in Mean Green
User avatar
Ron240
Posts: 770
Joined: Sat Jul 01, 2023 6:01 pm
Location: Fife

Post by Ron240 »

Using the link posted earlier in this thread the following 2 points are stated for every service in the 'Under Hood' category.
undefined Remove and install for access to spark plugs ("(use torque ", spark-plug-coil-torque, " Nm)")
undefined Renew ("(use torque ", spark-plug-torque, " Nm)")

It would be much clearer and easy to understand if it said renew spark plugs in the same sentence.

I have a 2 service plan already paid upfront, and as I said earlier I will be amazed if they change my plugs when I take it in for the first service.
First service is due end of June so naturally I will report back at that time.
Last edited by Ron240 on Wed Apr 03, 2024 9:06 am, edited 1 time in total.
2023 Puma ST (1.5 200PS), Desert Island Blue with Driver Assistance Pack.
FP2022F1T
Posts: 709
Joined: Sun Jun 12, 2022 8:41 am
Location: Northampton

Post by FP2022F1T »

matthen wrote: Wed Apr 03, 2024 8:34 am
Ron240 wrote: Wed Apr 03, 2024 12:21 am Reading through this thread regarding spark plugs...and my personal opinion is that it is ridiculous to change spark plugs every 12 months/12500 miles. I could understand it if it was an exotic car in a high state of tune...but its just a run of the mill Ford.
My car will have covered less than 3000 miles at 1 year old and I will be amazed if they routinely change the plugs.
It’s a 3 pot producing 200 BHP, complying with all sorts of emissions limits - I’d say that’s a fairly high state of tune 🙂

OP: how'd you know when it's in 2 cylinder mode? I've done 25K mi in mine, a good portion of them motorway, and I'd confidently say it has never deactivated a cylinder.
Same here if it is doing this on a journey I’m certainly not noticing it, if it’s on the ST at all

Old thread here viewtopic.php?t=1212
ST Performance Grey Matter (Performance Pack / Drivers Assistance Pack / Dark Wheels & Power Tailgate)
Fberlo
Posts: 5
Joined: Tue Apr 02, 2024 9:27 am

Post by Fberlo »

FP2022F1T wrote: Wed Apr 03, 2024 9:06 am
matthen wrote: Wed Apr 03, 2024 8:34 am
Ron240 wrote: Wed Apr 03, 2024 12:21 am Reading through this thread regarding spark plugs...and my personal opinion is that it is ridiculous to change spark plugs every 12 months/12500 miles. I could understand it if it was an exotic car in a high state of tune...but its just a run of the mill Ford.
My car will have covered less than 3000 miles at 1 year old and I will be amazed if they routinely change the plugs.
It’s a 3 pot producing 200 BHP, complying with all sorts of emissions limits - I’d say that’s a fairly high state of tune 🙂

OP: how'd you know when it's in 2 cylinder mode? I've done 25K mi in mine, a good portion of them motorway, and I'd confidently say it has never deactivated a cylinder.
Same here if it is doing this on a journey I’m certainly not noticing it, if it’s on the ST at all

Old thread here viewtopic.php?t=1212
Well when cruising and barely touching the gas pedal, the engine is a bit louder with a slight vibration. Instant fuel consumption drops significanlty.
It happens way more in eco mode, never in sport mode. Once you press the gas pedal 1 or 2 cm more, or going slightly uphill, it switches to 3 cylinder (engine sound changes a bit, less virbations)...
FP2022F1T
Posts: 709
Joined: Sun Jun 12, 2022 8:41 am
Location: Northampton

Post by FP2022F1T »

Fberlo wrote: Wed Apr 03, 2024 1:58 pm
FP2022F1T wrote: Wed Apr 03, 2024 9:06 am
matthen wrote: Wed Apr 03, 2024 8:34 am

It’s a 3 pot producing 200 BHP, complying with all sorts of emissions limits - I’d say that’s a fairly high state of tune 🙂

OP: how'd you know when it's in 2 cylinder mode? I've done 25K mi in mine, a good portion of them motorway, and I'd confidently say it has never deactivated a cylinder.
Same here if it is doing this on a journey I’m certainly not noticing it, if it’s on the ST at all

Old thread here viewtopic.php?t=1212
Well when cruising and barely touching the gas pedal, the engine is a bit louder with a slight vibration. Instant fuel consumption drops significanlty.
It happens way more in eco mode, never in sport mode. Once you press the gas pedal 1 or 2 cm more, or going slightly uphill, it switches to 3 cylinder (engine sound changes a bit, less virbations)...
Ok perhaps explains it never used ECO apart from when it snowed
Will try this out on my way home from work later
ST Performance Grey Matter (Performance Pack / Drivers Assistance Pack / Dark Wheels & Power Tailgate)
Mike
Posts: 1389
Joined: Wed Dec 23, 2020 9:15 pm
Location: North East

Post by Mike »

155 / 125 engines are every 2nd service along with the air filter or so i was told when i had mine.
So that could be every 4 yrs or 36 k
ST Line X 155 Agate Black with comfort pack plus spare wheel( sold :( )
User avatar
Chocky
Posts: 305
Joined: Sat Aug 15, 2020 11:26 pm

Post by Chocky »

Faulty cam position sensor would do this. Get the trouble codes read.
Post Reply