So here's an interesting one for you. I was out today in my GP, it's the 1.2 8v and I was moving along fairly rapidly about 130-140km/h and over 4k rpm when I got a check engine light flashing for a few seconds or so, then it went away and hasn't come back since. I didn't notice anything strange about the car's performance or behaviour, I went to see if I could get a fault code read but garage was closed. So I decided to go out and do a so-called "italian tune-up", gave it some high rev bursts on the open road, then went back to cruising at the same speed and revs as before and it didn't come back. What do you think? Spark plugs were changed about 7k miles ago, timing belt was changed over 20k miles ago.

What I suspect is that it was just an ECU hiccup or some kind of misreading, the reason I suspect this is that a couple of years ago I was cruising at 100km/h (3k rpm) and suddenly the check engine light came on and my temp dial rapidly shot up to hot for a split second, then rapidly went down to normal again and check engine light switched off. I had the car diagnosed and there was nothing wrong with it, obviously was an ECU hiccup since engine temp doesn't rise that quickly. Nothing similar has happened since then until now.

I should also note that it's very sweet to drive and if it weren't for the light flashing I would never have noticed anything, as there was no power loss etc as you would have with an actual misfire, at least nothing that I noticed. Needless to say oil and coolant are good and at correct levels, also the right colour and engine is tight as a drum so really don't think there's anything wrong with the engine but I'm no mechanic.

When the belt was changed was a phonic wheel relearn carried out?



As this is exactly the sort of circumstances an issue with this shows up high speed motorways driving often accompanied by a misfre code of the ECU due to small differences in the timing caused by changing a belt
Allthrough it tends to show up shortly after the belt change not this far down the line

I can't be absolutely sure if a relearn was done when I got the timing belt replaced but I'm fairly confident they did do it because as you say it's over 20k miles down the line and I have done short high speed motorway runs up to 150 km/hr without any issues, and went out for another run after the light flashed to see if it would come back but it didn't.