Hi there, my first post on this forum. My Wife has a 54plate 1.2 Fiesta, she drives to and from work but not many miles on it, only about 38k i think. I recently did a Oil, airfilter, and plug change. The car was running alot better and smooth, but after a week or so the car has started to be very jerky and sluggish to drive. Im not sure what this could be, my only thought is the Lambda Sensor? Any help or thoughts on this would be much appreciated. Cheers.

Hiya mate, tbh before changing the lambda sensor I'd be inclined to get a Ford garage to read the fault codes. I don't think they charge much and it might highlight a potential problem, at least that way you can be more certain of whatever the problem is, as it would be a right pain changing parts to find out the car is doing the same thing.

Is the engine light on? Also is the problem worse when the engine is cold, and goes once it's warmed up? If so it could be your idle air control valve they get filthy and can need a clean either with some special cleaner or a little bowl of petrol.

Dan

Hiya mate, tbh before changing the lambda sensor I'd be inclined to get a Ford garage to read the fault codes. I don't think they charge much and it might highlight a potential problem, at least that way you can be more certain of whatever the problem is, as it would be a right pain changing parts to find out the car is doing the same thing.

Is the engine light on? Also is the problem worse when the engine is cold, and goes once it's warmed up? If so it could be your idle air control valve they get filthy and can need a clean either with some special cleaner or a little bowl of petrol.

Dan

Hi dan, thanks for the quick reply. Yes, that does make sense. No the engine light isn't on, and it is worse when the engine is cold. I've booked the car into a good local garage tomorrow, so we'll see what they say. I'll post what the outcome is. At least the wife is happy, as she's taking my BMW tomorrow.

No problems mate I'm always glad to help! If the problem is worse when the engine is cold that leads me to believe the idle air control valve is a certain possibility. Their job is to control the air flow when the engine is cold, the same way a choke would on older engines. If they're clogged or faulty you'd often find the engine jerky when idling, and in some cases it won't tick over without stalling.

Another possibility is your airflow sensor, this reports back to the ECU information on air flow so it can inject the correct amount of fuel.

I miss the old Mini's because they were soooo simple and easy, cars now are getting so complicated :D.

Anyway I'll stop rambling, will look forward to an update!

Dan :)

Well, I checked the plugs and leads before I took it to the garage, found one of the leads wasn't fully pushed down on the plug. So made sure they all were fully pushed down on the plugs. The wife did say her car was alot better today. So for now I think its ok.

If only cars were as easy to fix as computers.