Hi 

New to here but hoping someone could maybe throw some advice my way !?, got 2006 fiesta zetec s,petrol ,it started with a slightly rough idle so sort of like slight coughing but nothing seemed to be affected till one day EML came on so plugged it in and it said O2 sensor bank 1 so changed lambda sensor and seemed little better but then rough idle came back about a few weeks after so plugged it in again and was saying the Lambda sensor again so we assumed maybe a faulty part got a new one put it on same again a little better but not much so decided to change coil pack and leads ,no change but car then started getting worse with coughing and no power then suddenly a surge !, or if you set off from standing it won't accelerate unless you floor it ,even if you are at a steady speed you can feel it being held back then not ,it's very strange as does it everyday but through out a drive it maybe ok but tends to start when your say waiting at a junction and the coughing get worse till it almost cutting out so you have to rev it .Anyway last week plugged it in and it was say body control module defective so we bought a second hand ECU kit off eBay and replaced ECU ,clocks ,ignition barrel and a box that was something to do with immobiliser/alarm ,basically a kit that I read up you needed to change ,so done all that and it's still doing same thing !, any ideas greatly taken ?, as I'm stuck as to what to do now ?, I'm going to plug car in tomorrow to see if any codes there but was wondering if the is something else folk have encountered.thanks 👍

 

don't they have two o2 sensor one before cat and one after 

Hi pal 

not sure ,I'll check tomorrow but perhaps that is it ? 

I had a 02 sensor replaced on my 2018 ecoboost the other week as the EML light came on. The sensor was the 2nd (further down the downpipe) and this is the report the AA gave

Patrol found the following fault code/s:System : Engine control 1 - 3Z1 / Motronic MED 17.0.7P013700 - O2 sensor (bank 1, sensor 2). Error Message : Signal too low.investigated engine management warning light on suspect oxygen sensor faulty sensor bank 1 sensor 2member taking into dealership for further diagnosis.

I might be wrong, but I don't think the 2nd 02 sensor affects the running of the engine, it monitors the exhaust to check that the catalytic converter is working effectively. If it thinks it is not it turns the light on, but I don't think it would affect performance.  But I don't guarantee I am correct here. 

it could be a wiring/connection fault possibly. When a fault code mentions a particular part, it does not neccessarily mean that part is faulty, it could be a bad connection with it. The fault codes give a clue to what is wrong,only a clue,  they are not gospel. 

 

Mine wasn't in limp mode and ran normal, it might have been a little rougher but didn't stall / stutter or give coughing symptons

It would have been cheaper to get a local garage with a full diagnostic reader to diagnose the problem than it was to replace all those parts - are you in the AA or RAC as you could call them saying the car wont start and they can run the test?