Hi all,

I have a 1.25 petrol engine MK6 fiesta.

It runs fine, except for between 1800 and 2000 RPM when I get a really strange judder/kangarooing when I'm accelerating. It happens in any gear.

I've plugged in my OBD2 reader, and I don't have any fault codes. I've tried some real-time logging, and that shows that the ignition advance and fuel flow both jitter a little when this jerking happens. The engine RPM readout also starts misreading upwards when this happens.

Anyone have any ideas what the root cause of this could be? It's had my head scratching for a while...