Hopefully someone can help. (Re posted as I missed out the vehicle engine size) This has left me & the garage baffled. I have a Mk 7 Fiesta (I believe 20212) 1.2l Zetec. When I start the car from cold, it start fine, then its as if the fuel is not getting through. It shudders as if its about to stall, then it seems to be ok no stall. Runs fine. But then if I stop and go back maybe 10 minutes later same again. Its had new battery & spark plugs & been into the local garage (Where typically it didn't materialise). Any help would really be appreciated to point me (or the garage in the right direction) The garage did say it possibly maybe the Coolant housing/Temp sensort. Is this a possibilty, I really don't want to be just throwing money at it. many thanks

Update, went out this morning, wouldn't start, turned over but wouldn't start. Left it half hour, tried again. Fired first time but running really rough. 🤬

I don't know if I responded to original post (would be helpful to point to it or continue it with correct details?)
Edit: It was in the guides section so best to avoid that, know what I mean! 😉

I HATE it when garages say they "think" or some other weasel words meaning they will start to change parts by guesswork at your cost, although, to be fair, without codes or diagnostic work they have no simple option?

However, we do, as there is Forscan where you can check the coolant temperature sensor reading that is being supplied to the PCM and monitor other live data and Ford specific codes WHEN THE FAULT IS PRESENT, WITHOUT SWITCHING OFF!
If temp is stupidly high or low or doesn't match the engine state then that is a big clue likewise all other parameters.
This may help to get enough clues to actually find the real fault!
I'm not going to post the details which are all over here (should be a sticky or I'll make my own soon) you can use laptop or phone app with appropriate dongle (laptop and phone) or lead (laptop only?)

Finding a competent new garage that you can actually trust would be a good starting point.

As above, Forscan will certainly help. Where's @unofix when you need his links?

It could be any number of different things that's causing your issue, without some form of proper diagnosis it's pure guesswork.

On 3/2/2026 at 7:54 PM, mickywrx said:

Finding a competent new garage that you can actually trust would be a good starting point.

As above, Forscan will certainly help. Where's @unofix when you need his links?

It could be any number of different things that's causing your issue, without some form of proper diagnosis it's pure guesswork.

Many thanks for this. To be fair, they are a really good garage & as both he and you said it is pure guesswork. Thanks for taking the time to reply,

Well update: Thought we'd sorted, seems not. Had new engine coolant temp sensor in. Was ok a day then went back to its old ways. Even thought it could be the imobiliser as it was only when starting. Nope.. So took back to the garage for it to again them to see if it will do the deed on them so they can diagnose it. Much as I love the Fiesta I am now seriously thinking of getting rid of it.