We have an Astra 1.4 multi point injection, would cut out for 5 to 20 mins. Had all sort of bits replaced by local garages. Turned out to be the Amplifer/Trigger unit which lives under the coil. And a little sod to get off it's heat sink. £45 from your local car parts, or a little more from Vauxhall. This post is for information only on a google search. Good old google.