Hello! 
im sorry if this has already been asked! I’ve looked all over the internet and am at a loss. 
 

I’ve got a 2010 1.4 fiesta, car drove completely fine until it started to loose power and judder mid drive. After stopping and trying to restart, it has a really rough idle then cuts out. If you keep the revs up, it drives, but has next to no power and cuts out as soon as it hits idle. 

the only code present is nox sensor
 

I’ve replaced: 

-Nox sensor 

-Cam shaft sensor

-Crank shaft sensor

-spark plugs

-leads

-coil pack

 

I’ve read a few posts about the idle air control sensor, this will be my next step but I wondered if anyone had any other possibilities, please?! 
 

thankyou! 🙂

6 minutes ago, Katy14 said:

the only code present is nox sensor

Are you using FORScan to read the DTCs or just a generic code reader ?

8 hours ago, unofix said:

Are you using FORScan to read the DTCs or just a generic code reader ?

It’s an Autel scanner  

11 hours ago, Katy14 said:

It’s an Autel scanner  

That explains why you are not seeing the Ford specific DTC's

There isn't a NOx sensor on these.

I suspect the code is for the O2 sensor?

Can you tell us the exact code, as some are for the sensor wiring rather than the 'sensing'.  It could also be an exhaust leak, or a vacuum leak, affecting the sensor readings.

I must admit this sounds like a slipped timing belt though.  Do you know when the belt was last changed?

On 9/25/2024 at 7:40 PM, TomsFocus said:

There isn't a NOx sensor on these.

I suspect the code is for the O2 sensor?

Can you tell us the exact code, as some are for the sensor wiring rather than the 'sensing'.  It could also be an exhaust leak, or a vacuum leak, affecting the sensor readings.

I must admit this sounds like a slipped timing belt though.  Do you know when the belt was last changed?

Thankyou for this! 

I dont have the exact code to hand, however i can get this today and then let you know! 

We also thought it sounded like the belt. I don't have an exact time/ millage however i know it was done before we owned it. Its been in the family for 3/4 years.

oh right okay! thankyou

5 hours ago, Katy14 said:

Thankyou for this! 

I dont have the exact code to hand, however i can get this today and then let you know! 

We also thought it sounded like the belt. I don't have an exact time/ millage however i know it was done before we owned it. It’s been in the family for 3/4 years.

 So these are the codes we got today, pretty sure different to the last time it was plugged in. I think where I’ve said nox I mean knock 🫣 sorry! It either way.. ignore the throttle actuator code, it had a sensor unplugged at the time of the code reading! 
 

Belt has been checked,  looks fine! Got confirmation today that the belt was done 30k miles ago! 

Ah, knock sensor makes a bit more sense.  However, that's still pointing towards timing being off, causing genuine knock.  That is usually caused by a slipped cambelt.  Was the cover fully removed to check the timing of both cams and crank or just a quick look to see one small section of belt condition?