Hi all im a newbie here, was wondering if some of you guys could help me. I have had my fiesta mk5 1.25 since august and its been a good car. However about a month ago it started being lumpy on cold startup. As the warm/ hot startup was fine i figured it may be damp on the plugs and leads, so i replaced the plugs with ngk items supplied from my local motor factors, They were the same make and part number as what i removed and new silicone leads. The problem however still persists so my next step was spraying all electrical plugs and connections under the bonnet with WD40 but again it is still lumpy on cold start. The lumpiness only lasts 1 to 3 seconds before it stabilises itself but its not a nice feeling when im thinking of the possibility of unburnt fuel going through the cat. Please has anybody got any ideas?

 

bump

 

Could just be a slow lambda, a lot slow with age, but dead easy on yours to do, but jesus can they get tight on these, manifolds have been known to break/threads when trying to remove the sensor, so get nice and warm first.
tabetha

 

mine did exactly the same thing, it got worse and now it misfires. im going to post up my problem so keep an eye on it incase someone can answers my question

 

Thanks all.