Engine query???

[mlebon]

Hi guys, I'm new on here but a huge fan of forums as they are just a mass of info and help and always check them out when having motoring probs.
My son has a 2001 1.1 Saxo and told me today that it has developed a symptom where the EML comes on at around 80mph along with some stuttering. Then got into it following day and the EML was no longer on - but had not driven it fast since. Anyone have any ideas as to the problem here? I don't have access to a diagnostics handset, other than taking it to the garage - I always try and sort stuff out myself if I can. Would be greatful for any suggestions.
It had a basic service a few months ago along with new spark plugs.

Thanks in advance!!