Hey there

Hope you guys can help me. I own a 02 1.3 Ford Focus. For the past few months whenever I come to stop and the rev counter reaches its idle speed when warmed up the car will shudder for a few seconds then sort itself out. I've noticed it dips slightly below the usual idle rev speed and the dash display will dim in time with the shudder. This is even worse if I have the headlights on or the brake lights and I have to keep stopping in traffic. If I'm stationary and put the blowers on it will keep shuddering and the car will vibrate badly with the same display dimming. If I start going again in 1st gear and use the blowers I'll instantly feel a loss of power to the engine as well but that disappears once I'm at speed.

I just had it's MOT done and asked the garage to take a look at this at the same time and they said that the alternator was faulty and not putting out enough voltage which they replaced with the battery. Drove it him and as soon as I get to my driveway and put the clutch in I feel it again and same symptoms above as before. I took it back as i was not happy with paying for a new alt and battery so they test drove it and couldn't find anything wrong.

Looking at a few forums and youtube vids I found another person with the same fault. They were told it's the ICV so today I cleaned that out and reset the ECU and took it for a run but no difference so I'm at my wits end with it. Sitting in traffic freezing cold with a fogged up windscreen is not fun!

I'd appreciate any help with this before I take it too a different garage. Have also read that updating the ECU will solve the rough idle?

Thanks in advance

Hi welcome :)

my sons car does the same thing but runs fine the rest of the time we think it may need the ecu upgrading

Thanks Dezwez, I've just been thinking about this as I've also read it could be a vacuum leak or PCV but then if that's the case then surely the shudder would be constant and use of electrics wouldn't matter?