Been having a weird problem that probably wiring-related... every so often the MPG and avaerage speed readouts reset on my car. This happens when car is started up - the dials shudder before coming online. Then the ECU acts as if it's in training mode for a week or so.
It's like the behaviour when the ECU has been reset by disconnecting the battery - execept all other things that are normally reset are fine (radio/trip distance).
Been happening since early this year - but thought it was down to some faulty sheared wiring from the ignition system to the coil pack connector - but this is now all sorted.
Have tested battery and alternator, volatages etc are fine.
Any ideas/thoughts, or similar experiences?